caps.c 80.9 KB
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#include "ceph_debug.h"

#include <linux/fs.h>
#include <linux/kernel.h>
#include <linux/sched.h>
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#include <linux/slab.h>
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#include <linux/vmalloc.h>
#include <linux/wait.h>
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#include <linux/writeback.h>
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#include "super.h"
#include "decode.h"
#include "messenger.h"

/*
 * Capability management
 *
 * The Ceph metadata servers control client access to inode metadata
 * and file data by issuing capabilities, granting clients permission
 * to read and/or write both inode field and file data to OSDs
 * (storage nodes).  Each capability consists of a set of bits
 * indicating which operations are allowed.
 *
 * If the client holds a *_SHARED cap, the client has a coherent value
 * that can be safely read from the cached inode.
 *
 * In the case of a *_EXCL (exclusive) or FILE_WR capabilities, the
 * client is allowed to change inode attributes (e.g., file size,
 * mtime), note its dirty state in the ceph_cap, and asynchronously
 * flush that metadata change to the MDS.
 *
 * In the event of a conflicting operation (perhaps by another
 * client), the MDS will revoke the conflicting client capabilities.
 *
 * In order for a client to cache an inode, it must hold a capability
 * with at least one MDS server.  When inodes are released, release
 * notifications are batched and periodically sent en masse to the MDS
 * cluster to release server state.
 */


/*
 * Generate readable cap strings for debugging output.
 */
#define MAX_CAP_STR 20
static char cap_str[MAX_CAP_STR][40];
static DEFINE_SPINLOCK(cap_str_lock);
static int last_cap_str;

static char *gcap_string(char *s, int c)
{
	if (c & CEPH_CAP_GSHARED)
		*s++ = 's';
	if (c & CEPH_CAP_GEXCL)
		*s++ = 'x';
	if (c & CEPH_CAP_GCACHE)
		*s++ = 'c';
	if (c & CEPH_CAP_GRD)
		*s++ = 'r';
	if (c & CEPH_CAP_GWR)
		*s++ = 'w';
	if (c & CEPH_CAP_GBUFFER)
		*s++ = 'b';
	if (c & CEPH_CAP_GLAZYIO)
		*s++ = 'l';
	return s;
}

const char *ceph_cap_string(int caps)
{
	int i;
	char *s;
	int c;

	spin_lock(&cap_str_lock);
	i = last_cap_str++;
	if (last_cap_str == MAX_CAP_STR)
		last_cap_str = 0;
	spin_unlock(&cap_str_lock);

	s = cap_str[i];

	if (caps & CEPH_CAP_PIN)
		*s++ = 'p';

	c = (caps >> CEPH_CAP_SAUTH) & 3;
	if (c) {
		*s++ = 'A';
		s = gcap_string(s, c);
	}

	c = (caps >> CEPH_CAP_SLINK) & 3;
	if (c) {
		*s++ = 'L';
		s = gcap_string(s, c);
	}

	c = (caps >> CEPH_CAP_SXATTR) & 3;
	if (c) {
		*s++ = 'X';
		s = gcap_string(s, c);
	}

	c = caps >> CEPH_CAP_SFILE;
	if (c) {
		*s++ = 'F';
		s = gcap_string(s, c);
	}

	if (s == cap_str[i])
		*s++ = '-';
	*s = 0;
	return cap_str[i];
}

/*
 * Cap reservations
 *
 * Maintain a global pool of preallocated struct ceph_caps, referenced
 * by struct ceph_caps_reservations.  This ensures that we preallocate
 * memory needed to successfully process an MDS response.  (If an MDS
 * sends us cap information and we fail to process it, we will have
 * problems due to the client and MDS being out of sync.)
 *
 * Reservations are 'owned' by a ceph_cap_reservation context.
 */
static spinlock_t caps_list_lock;
static struct list_head caps_list;  /* unused (reserved or unreserved) */
static int caps_total_count;        /* total caps allocated */
static int caps_use_count;          /* in use */
static int caps_reserve_count;      /* unused, reserved */
static int caps_avail_count;        /* unused, unreserved */
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static int caps_min_count;          /* keep at least this many (unreserved) */
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void __init ceph_caps_init(void)
{
	INIT_LIST_HEAD(&caps_list);
	spin_lock_init(&caps_list_lock);
}

void ceph_caps_finalize(void)
{
	struct ceph_cap *cap;

	spin_lock(&caps_list_lock);
	while (!list_empty(&caps_list)) {
		cap = list_first_entry(&caps_list, struct ceph_cap, caps_item);
		list_del(&cap->caps_item);
		kmem_cache_free(ceph_cap_cachep, cap);
	}
	caps_total_count = 0;
	caps_avail_count = 0;
	caps_use_count = 0;
	caps_reserve_count = 0;
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	caps_min_count = 0;
	spin_unlock(&caps_list_lock);
}

void ceph_adjust_min_caps(int delta)
{
	spin_lock(&caps_list_lock);
	caps_min_count += delta;
	BUG_ON(caps_min_count < 0);
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	spin_unlock(&caps_list_lock);
}

int ceph_reserve_caps(struct ceph_cap_reservation *ctx, int need)
{
	int i;
	struct ceph_cap *cap;
	int have;
	int alloc = 0;
	LIST_HEAD(newcaps);
	int ret = 0;

	dout("reserve caps ctx=%p need=%d\n", ctx, need);

	/* first reserve any caps that are already allocated */
	spin_lock(&caps_list_lock);
	if (caps_avail_count >= need)
		have = need;
	else
		have = caps_avail_count;
	caps_avail_count -= have;
	caps_reserve_count += have;
	BUG_ON(caps_total_count != caps_use_count + caps_reserve_count +
	       caps_avail_count);
	spin_unlock(&caps_list_lock);

	for (i = have; i < need; i++) {
		cap = kmem_cache_alloc(ceph_cap_cachep, GFP_NOFS);
		if (!cap) {
			ret = -ENOMEM;
			goto out_alloc_count;
		}
		list_add(&cap->caps_item, &newcaps);
		alloc++;
	}
	BUG_ON(have + alloc != need);

	spin_lock(&caps_list_lock);
	caps_total_count += alloc;
	caps_reserve_count += alloc;
	list_splice(&newcaps, &caps_list);

	BUG_ON(caps_total_count != caps_use_count + caps_reserve_count +
	       caps_avail_count);
	spin_unlock(&caps_list_lock);

	ctx->count = need;
	dout("reserve caps ctx=%p %d = %d used + %d resv + %d avail\n",
	     ctx, caps_total_count, caps_use_count, caps_reserve_count,
	     caps_avail_count);
	return 0;

out_alloc_count:
	/* we didn't manage to reserve as much as we needed */
	pr_warning("reserve caps ctx=%p ENOMEM need=%d got=%d\n",
		   ctx, need, have);
	return ret;
}

int ceph_unreserve_caps(struct ceph_cap_reservation *ctx)
{
	dout("unreserve caps ctx=%p count=%d\n", ctx, ctx->count);
	if (ctx->count) {
		spin_lock(&caps_list_lock);
		BUG_ON(caps_reserve_count < ctx->count);
		caps_reserve_count -= ctx->count;
		caps_avail_count += ctx->count;
		ctx->count = 0;
		dout("unreserve caps %d = %d used + %d resv + %d avail\n",
		     caps_total_count, caps_use_count, caps_reserve_count,
		     caps_avail_count);
		BUG_ON(caps_total_count != caps_use_count + caps_reserve_count +
		       caps_avail_count);
		spin_unlock(&caps_list_lock);
	}
	return 0;
}

static struct ceph_cap *get_cap(struct ceph_cap_reservation *ctx)
{
	struct ceph_cap *cap = NULL;

	/* temporary, until we do something about cap import/export */
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	if (!ctx) {
		cap = kmem_cache_alloc(ceph_cap_cachep, GFP_NOFS);
		if (cap) {
			caps_use_count++;
			caps_total_count++;
		}
		return cap;
	}
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	spin_lock(&caps_list_lock);
	dout("get_cap ctx=%p (%d) %d = %d used + %d resv + %d avail\n",
	     ctx, ctx->count, caps_total_count, caps_use_count,
	     caps_reserve_count, caps_avail_count);
	BUG_ON(!ctx->count);
	BUG_ON(ctx->count > caps_reserve_count);
	BUG_ON(list_empty(&caps_list));

	ctx->count--;
	caps_reserve_count--;
	caps_use_count++;

	cap = list_first_entry(&caps_list, struct ceph_cap, caps_item);
	list_del(&cap->caps_item);

	BUG_ON(caps_total_count != caps_use_count + caps_reserve_count +
	       caps_avail_count);
	spin_unlock(&caps_list_lock);
	return cap;
}

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void ceph_put_cap(struct ceph_cap *cap)
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{
	spin_lock(&caps_list_lock);
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	dout("put_cap %p %d = %d used + %d resv + %d avail\n",
	     cap, caps_total_count, caps_use_count,
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	     caps_reserve_count, caps_avail_count);
	caps_use_count--;
	/*
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	 * Keep some preallocated caps around (ceph_min_count), to
	 * avoid lots of free/alloc churn.
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	 */
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	if (caps_avail_count >= caps_reserve_count + caps_min_count) {
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		caps_total_count--;
		kmem_cache_free(ceph_cap_cachep, cap);
	} else {
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		caps_avail_count++;
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		list_add(&cap->caps_item, &caps_list);
	}

	BUG_ON(caps_total_count != caps_use_count + caps_reserve_count +
	       caps_avail_count);
	spin_unlock(&caps_list_lock);
}

void ceph_reservation_status(struct ceph_client *client,
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			     int *total, int *avail, int *used, int *reserved,
			     int *min)
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{
	if (total)
		*total = caps_total_count;
	if (avail)
		*avail = caps_avail_count;
	if (used)
		*used = caps_use_count;
	if (reserved)
		*reserved = caps_reserve_count;
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	if (min)
		*min = caps_min_count;
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}

/*
 * Find ceph_cap for given mds, if any.
 *
 * Called with i_lock held.
 */
static struct ceph_cap *__get_cap_for_mds(struct ceph_inode_info *ci, int mds)
{
	struct ceph_cap *cap;
	struct rb_node *n = ci->i_caps.rb_node;

	while (n) {
		cap = rb_entry(n, struct ceph_cap, ci_node);
		if (mds < cap->mds)
			n = n->rb_left;
		else if (mds > cap->mds)
			n = n->rb_right;
		else
			return cap;
	}
	return NULL;
}

/*
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 * Return id of any MDS with a cap, preferably FILE_WR|BUFFER|EXCL, else -1.
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 */
static int __ceph_get_cap_mds(struct ceph_inode_info *ci, u32 *mseq)
{
	struct ceph_cap *cap;
	int mds = -1;
	struct rb_node *p;

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	/* prefer mds with WR|BUFFER|EXCL caps */
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	for (p = rb_first(&ci->i_caps); p; p = rb_next(p)) {
		cap = rb_entry(p, struct ceph_cap, ci_node);
		mds = cap->mds;
		if (mseq)
			*mseq = cap->mseq;
		if (cap->issued & (CEPH_CAP_FILE_WR |
				   CEPH_CAP_FILE_BUFFER |
				   CEPH_CAP_FILE_EXCL))
			break;
	}
	return mds;
}

int ceph_get_cap_mds(struct inode *inode)
{
	int mds;
	spin_lock(&inode->i_lock);
	mds = __ceph_get_cap_mds(ceph_inode(inode), NULL);
	spin_unlock(&inode->i_lock);
	return mds;
}

/*
 * Called under i_lock.
 */
static void __insert_cap_node(struct ceph_inode_info *ci,
			      struct ceph_cap *new)
{
	struct rb_node **p = &ci->i_caps.rb_node;
	struct rb_node *parent = NULL;
	struct ceph_cap *cap = NULL;

	while (*p) {
		parent = *p;
		cap = rb_entry(parent, struct ceph_cap, ci_node);
		if (new->mds < cap->mds)
			p = &(*p)->rb_left;
		else if (new->mds > cap->mds)
			p = &(*p)->rb_right;
		else
			BUG();
	}

	rb_link_node(&new->ci_node, parent, p);
	rb_insert_color(&new->ci_node, &ci->i_caps);
}

/*
 * (re)set cap hold timeouts, which control the delayed release
 * of unused caps back to the MDS.  Should be called on cap use.
 */
static void __cap_set_timeouts(struct ceph_mds_client *mdsc,
			       struct ceph_inode_info *ci)
{
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	struct ceph_mount_args *ma = mdsc->client->mount_args;
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	ci->i_hold_caps_min = round_jiffies(jiffies +
					    ma->caps_wanted_delay_min * HZ);
	ci->i_hold_caps_max = round_jiffies(jiffies +
					    ma->caps_wanted_delay_max * HZ);
	dout("__cap_set_timeouts %p min %lu max %lu\n", &ci->vfs_inode,
	     ci->i_hold_caps_min - jiffies, ci->i_hold_caps_max - jiffies);
}

/*
 * (Re)queue cap at the end of the delayed cap release list.
 *
 * If I_FLUSH is set, leave the inode at the front of the list.
 *
 * Caller holds i_lock
 *    -> we take mdsc->cap_delay_lock
 */
static void __cap_delay_requeue(struct ceph_mds_client *mdsc,
				struct ceph_inode_info *ci)
{
	__cap_set_timeouts(mdsc, ci);
	dout("__cap_delay_requeue %p flags %d at %lu\n", &ci->vfs_inode,
	     ci->i_ceph_flags, ci->i_hold_caps_max);
	if (!mdsc->stopping) {
		spin_lock(&mdsc->cap_delay_lock);
		if (!list_empty(&ci->i_cap_delay_list)) {
			if (ci->i_ceph_flags & CEPH_I_FLUSH)
				goto no_change;
			list_del_init(&ci->i_cap_delay_list);
		}
		list_add_tail(&ci->i_cap_delay_list, &mdsc->cap_delay_list);
no_change:
		spin_unlock(&mdsc->cap_delay_lock);
	}
}

/*
 * Queue an inode for immediate writeback.  Mark inode with I_FLUSH,
 * indicating we should send a cap message to flush dirty metadata
 * asap, and move to the front of the delayed cap list.
 */
static void __cap_delay_requeue_front(struct ceph_mds_client *mdsc,
				      struct ceph_inode_info *ci)
{
	dout("__cap_delay_requeue_front %p\n", &ci->vfs_inode);
	spin_lock(&mdsc->cap_delay_lock);
	ci->i_ceph_flags |= CEPH_I_FLUSH;
	if (!list_empty(&ci->i_cap_delay_list))
		list_del_init(&ci->i_cap_delay_list);
	list_add(&ci->i_cap_delay_list, &mdsc->cap_delay_list);
	spin_unlock(&mdsc->cap_delay_lock);
}

/*
 * Cancel delayed work on cap.
 *
 * Caller must hold i_lock.
 */
static void __cap_delay_cancel(struct ceph_mds_client *mdsc,
			       struct ceph_inode_info *ci)
{
	dout("__cap_delay_cancel %p\n", &ci->vfs_inode);
	if (list_empty(&ci->i_cap_delay_list))
		return;
	spin_lock(&mdsc->cap_delay_lock);
	list_del_init(&ci->i_cap_delay_list);
	spin_unlock(&mdsc->cap_delay_lock);
}

/*
 * Common issue checks for add_cap, handle_cap_grant.
 */
static void __check_cap_issue(struct ceph_inode_info *ci, struct ceph_cap *cap,
			      unsigned issued)
{
	unsigned had = __ceph_caps_issued(ci, NULL);

	/*
	 * Each time we receive FILE_CACHE anew, we increment
	 * i_rdcache_gen.
	 */
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	if ((issued & (CEPH_CAP_FILE_CACHE|CEPH_CAP_FILE_LAZYIO)) &&
	    (had & (CEPH_CAP_FILE_CACHE|CEPH_CAP_FILE_LAZYIO)) == 0)
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		ci->i_rdcache_gen++;

	/*
	 * if we are newly issued FILE_SHARED, clear I_COMPLETE; we
	 * don't know what happened to this directory while we didn't
	 * have the cap.
	 */
	if ((issued & CEPH_CAP_FILE_SHARED) &&
	    (had & CEPH_CAP_FILE_SHARED) == 0) {
		ci->i_shared_gen++;
		if (S_ISDIR(ci->vfs_inode.i_mode)) {
			dout(" marking %p NOT complete\n", &ci->vfs_inode);
			ci->i_ceph_flags &= ~CEPH_I_COMPLETE;
		}
	}
}

/*
 * Add a capability under the given MDS session.
 *
 * Caller should hold session snap_rwsem (read) and s_mutex.
 *
 * @fmode is the open file mode, if we are opening a file, otherwise
 * it is < 0.  (This is so we can atomically add the cap and add an
 * open file reference to it.)
 */
int ceph_add_cap(struct inode *inode,
		 struct ceph_mds_session *session, u64 cap_id,
		 int fmode, unsigned issued, unsigned wanted,
		 unsigned seq, unsigned mseq, u64 realmino, int flags,
		 struct ceph_cap_reservation *caps_reservation)
{
	struct ceph_mds_client *mdsc = &ceph_inode_to_client(inode)->mdsc;
	struct ceph_inode_info *ci = ceph_inode(inode);
	struct ceph_cap *new_cap = NULL;
	struct ceph_cap *cap;
	int mds = session->s_mds;
	int actual_wanted;

	dout("add_cap %p mds%d cap %llx %s seq %d\n", inode,
	     session->s_mds, cap_id, ceph_cap_string(issued), seq);

	/*
	 * If we are opening the file, include file mode wanted bits
	 * in wanted.
	 */
	if (fmode >= 0)
		wanted |= ceph_caps_for_mode(fmode);

retry:
	spin_lock(&inode->i_lock);
	cap = __get_cap_for_mds(ci, mds);
	if (!cap) {
		if (new_cap) {
			cap = new_cap;
			new_cap = NULL;
		} else {
			spin_unlock(&inode->i_lock);
			new_cap = get_cap(caps_reservation);
			if (new_cap == NULL)
				return -ENOMEM;
			goto retry;
		}

		cap->issued = 0;
		cap->implemented = 0;
		cap->mds = mds;
		cap->mds_wanted = 0;

		cap->ci = ci;
		__insert_cap_node(ci, cap);

		/* clear out old exporting info?  (i.e. on cap import) */
		if (ci->i_cap_exporting_mds == mds) {
			ci->i_cap_exporting_issued = 0;
			ci->i_cap_exporting_mseq = 0;
			ci->i_cap_exporting_mds = -1;
		}

		/* add to session cap list */
		cap->session = session;
		spin_lock(&session->s_cap_lock);
		list_add_tail(&cap->session_caps, &session->s_caps);
		session->s_nr_caps++;
		spin_unlock(&session->s_cap_lock);
	}

	if (!ci->i_snap_realm) {
		/*
		 * add this inode to the appropriate snap realm
		 */
		struct ceph_snap_realm *realm = ceph_lookup_snap_realm(mdsc,
							       realmino);
		if (realm) {
			ceph_get_snap_realm(mdsc, realm);
			spin_lock(&realm->inodes_with_caps_lock);
			ci->i_snap_realm = realm;
			list_add(&ci->i_snap_realm_item,
				 &realm->inodes_with_caps);
			spin_unlock(&realm->inodes_with_caps_lock);
		} else {
			pr_err("ceph_add_cap: couldn't find snap realm %llx\n",
			       realmino);
		}
	}

	__check_cap_issue(ci, cap, issued);

	/*
	 * If we are issued caps we don't want, or the mds' wanted
	 * value appears to be off, queue a check so we'll release
	 * later and/or update the mds wanted value.
	 */
	actual_wanted = __ceph_caps_wanted(ci);
	if ((wanted & ~actual_wanted) ||
	    (issued & ~actual_wanted & CEPH_CAP_ANY_WR)) {
		dout(" issued %s, mds wanted %s, actual %s, queueing\n",
		     ceph_cap_string(issued), ceph_cap_string(wanted),
		     ceph_cap_string(actual_wanted));
		__cap_delay_requeue(mdsc, ci);
	}

	if (flags & CEPH_CAP_FLAG_AUTH)
		ci->i_auth_cap = cap;
	else if (ci->i_auth_cap == cap)
		ci->i_auth_cap = NULL;

	dout("add_cap inode %p (%llx.%llx) cap %p %s now %s seq %d mds%d\n",
	     inode, ceph_vinop(inode), cap, ceph_cap_string(issued),
	     ceph_cap_string(issued|cap->issued), seq, mds);
	cap->cap_id = cap_id;
	cap->issued = issued;
	cap->implemented |= issued;
	cap->mds_wanted |= wanted;
	cap->seq = seq;
	cap->issue_seq = seq;
	cap->mseq = mseq;
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	cap->cap_gen = session->s_cap_gen;
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	if (fmode >= 0)
		__ceph_get_fmode(ci, fmode);
	spin_unlock(&inode->i_lock);
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	wake_up_all(&ci->i_cap_wq);
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	return 0;
}

/*
 * Return true if cap has not timed out and belongs to the current
 * generation of the MDS session (i.e. has not gone 'stale' due to
 * us losing touch with the mds).
 */
static int __cap_is_valid(struct ceph_cap *cap)
{
	unsigned long ttl;
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	u32 gen;
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	spin_lock(&cap->session->s_cap_lock);
	gen = cap->session->s_cap_gen;
	ttl = cap->session->s_cap_ttl;
	spin_unlock(&cap->session->s_cap_lock);

648
	if (cap->cap_gen < gen || time_after_eq(jiffies, ttl)) {
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		dout("__cap_is_valid %p cap %p issued %s "
		     "but STALE (gen %u vs %u)\n", &cap->ci->vfs_inode,
651
		     cap, ceph_cap_string(cap->issued), cap->cap_gen, gen);
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		return 0;
	}

	return 1;
}

/*
 * Return set of valid cap bits issued to us.  Note that caps time
 * out, and may be invalidated in bulk if the client session times out
 * and session->s_cap_gen is bumped.
 */
int __ceph_caps_issued(struct ceph_inode_info *ci, int *implemented)
{
665
	int have = ci->i_snap_caps | ci->i_cap_exporting_issued;
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	struct ceph_cap *cap;
	struct rb_node *p;

	if (implemented)
		*implemented = 0;
	for (p = rb_first(&ci->i_caps); p; p = rb_next(p)) {
		cap = rb_entry(p, struct ceph_cap, ci_node);
		if (!__cap_is_valid(cap))
			continue;
		dout("__ceph_caps_issued %p cap %p issued %s\n",
		     &ci->vfs_inode, cap, ceph_cap_string(cap->issued));
		have |= cap->issued;
		if (implemented)
			*implemented |= cap->implemented;
	}
	return have;
}

/*
 * Get cap bits issued by caps other than @ocap
 */
int __ceph_caps_issued_other(struct ceph_inode_info *ci, struct ceph_cap *ocap)
{
	int have = ci->i_snap_caps;
	struct ceph_cap *cap;
	struct rb_node *p;

	for (p = rb_first(&ci->i_caps); p; p = rb_next(p)) {
		cap = rb_entry(p, struct ceph_cap, ci_node);
		if (cap == ocap)
			continue;
		if (!__cap_is_valid(cap))
			continue;
		have |= cap->issued;
	}
	return have;
}

/*
 * Move a cap to the end of the LRU (oldest caps at list head, newest
 * at list tail).
 */
static void __touch_cap(struct ceph_cap *cap)
{
	struct ceph_mds_session *s = cap->session;

	spin_lock(&s->s_cap_lock);
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	if (s->s_cap_iterator == NULL) {
714 715 716 717 718 719 720
		dout("__touch_cap %p cap %p mds%d\n", &cap->ci->vfs_inode, cap,
		     s->s_mds);
		list_move_tail(&cap->session_caps, &s->s_caps);
	} else {
		dout("__touch_cap %p cap %p mds%d NOP, iterating over caps\n",
		     &cap->ci->vfs_inode, cap, s->s_mds);
	}
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	spin_unlock(&s->s_cap_lock);
}

/*
 * Check if we hold the given mask.  If so, move the cap(s) to the
 * front of their respective LRUs.  (This is the preferred way for
 * callers to check for caps they want.)
 */
int __ceph_caps_issued_mask(struct ceph_inode_info *ci, int mask, int touch)
{
	struct ceph_cap *cap;
	struct rb_node *p;
	int have = ci->i_snap_caps;

	if ((have & mask) == mask) {
		dout("__ceph_caps_issued_mask %p snap issued %s"
		     " (mask %s)\n", &ci->vfs_inode,
		     ceph_cap_string(have),
		     ceph_cap_string(mask));
		return 1;
	}

	for (p = rb_first(&ci->i_caps); p; p = rb_next(p)) {
		cap = rb_entry(p, struct ceph_cap, ci_node);
		if (!__cap_is_valid(cap))
			continue;
		if ((cap->issued & mask) == mask) {
			dout("__ceph_caps_issued_mask %p cap %p issued %s"
			     " (mask %s)\n", &ci->vfs_inode, cap,
			     ceph_cap_string(cap->issued),
			     ceph_cap_string(mask));
			if (touch)
				__touch_cap(cap);
			return 1;
		}

		/* does a combination of caps satisfy mask? */
		have |= cap->issued;
		if ((have & mask) == mask) {
			dout("__ceph_caps_issued_mask %p combo issued %s"
			     " (mask %s)\n", &ci->vfs_inode,
			     ceph_cap_string(cap->issued),
			     ceph_cap_string(mask));
			if (touch) {
				struct rb_node *q;

				/* touch this + preceeding caps */
				__touch_cap(cap);
				for (q = rb_first(&ci->i_caps); q != p;
				     q = rb_next(q)) {
					cap = rb_entry(q, struct ceph_cap,
						       ci_node);
					if (!__cap_is_valid(cap))
						continue;
					__touch_cap(cap);
				}
			}
			return 1;
		}
	}

	return 0;
}

/*
 * Return true if mask caps are currently being revoked by an MDS.
 */
int ceph_caps_revoking(struct ceph_inode_info *ci, int mask)
{
	struct inode *inode = &ci->vfs_inode;
	struct ceph_cap *cap;
	struct rb_node *p;
	int ret = 0;

	spin_lock(&inode->i_lock);
	for (p = rb_first(&ci->i_caps); p; p = rb_next(p)) {
		cap = rb_entry(p, struct ceph_cap, ci_node);
		if (__cap_is_valid(cap) &&
		    (cap->implemented & ~cap->issued & mask)) {
			ret = 1;
			break;
		}
	}
	spin_unlock(&inode->i_lock);
	dout("ceph_caps_revoking %p %s = %d\n", inode,
	     ceph_cap_string(mask), ret);
	return ret;
}

int __ceph_caps_used(struct ceph_inode_info *ci)
{
	int used = 0;
	if (ci->i_pin_ref)
		used |= CEPH_CAP_PIN;
	if (ci->i_rd_ref)
		used |= CEPH_CAP_FILE_RD;
	if (ci->i_rdcache_ref || ci->i_rdcache_gen)
		used |= CEPH_CAP_FILE_CACHE;
	if (ci->i_wr_ref)
		used |= CEPH_CAP_FILE_WR;
	if (ci->i_wrbuffer_ref)
		used |= CEPH_CAP_FILE_BUFFER;
	return used;
}

/*
 * wanted, by virtue of open file modes
 */
int __ceph_caps_file_wanted(struct ceph_inode_info *ci)
{
	int want = 0;
	int mode;
833
	for (mode = 0; mode < CEPH_FILE_MODE_NUM; mode++)
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		if (ci->i_nr_by_mode[mode])
			want |= ceph_caps_for_mode(mode);
	return want;
}

/*
 * Return caps we have registered with the MDS(s) as 'wanted'.
 */
int __ceph_caps_mds_wanted(struct ceph_inode_info *ci)
{
	struct ceph_cap *cap;
	struct rb_node *p;
	int mds_wanted = 0;

	for (p = rb_first(&ci->i_caps); p; p = rb_next(p)) {
		cap = rb_entry(p, struct ceph_cap, ci_node);
		if (!__cap_is_valid(cap))
			continue;
		mds_wanted |= cap->mds_wanted;
	}
	return mds_wanted;
}

/*
 * called under i_lock
 */
static int __ceph_is_any_caps(struct ceph_inode_info *ci)
{
	return !RB_EMPTY_ROOT(&ci->i_caps) || ci->i_cap_exporting_mds >= 0;
}

/*
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 * Remove a cap.  Take steps to deal with a racing iterate_session_caps.
 *
868 869
 * caller should hold i_lock.
 * caller will not hold session s_mutex if called from destroy_inode.
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 */
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void __ceph_remove_cap(struct ceph_cap *cap)
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{
	struct ceph_mds_session *session = cap->session;
	struct ceph_inode_info *ci = cap->ci;
875 876
	struct ceph_mds_client *mdsc =
		&ceph_sb_to_client(ci->vfs_inode.i_sb)->mdsc;
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	int removed = 0;
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	dout("__ceph_remove_cap %p from %p\n", cap, &ci->vfs_inode);

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	/* remove from session list */
	spin_lock(&session->s_cap_lock);
	if (session->s_cap_iterator == cap) {
		/* not yet, we are iterating over this very cap */
		dout("__ceph_remove_cap  delaying %p removal from session %p\n",
		     cap, cap->session);
	} else {
		list_del_init(&cap->session_caps);
		session->s_nr_caps--;
		cap->session = NULL;
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		removed = 1;
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	}
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	/* protect backpointer with s_cap_lock: see iterate_session_caps */
	cap->ci = NULL;
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	spin_unlock(&session->s_cap_lock);

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	/* remove from inode list */
	rb_erase(&cap->ci_node, &ci->i_caps);
	if (ci->i_auth_cap == cap)
		ci->i_auth_cap = NULL;

	if (removed)
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		ceph_put_cap(cap);
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	if (!__ceph_is_any_caps(ci) && ci->i_snap_realm) {
		struct ceph_snap_realm *realm = ci->i_snap_realm;
		spin_lock(&realm->inodes_with_caps_lock);
		list_del_init(&ci->i_snap_realm_item);
		ci->i_snap_realm_counter++;
		ci->i_snap_realm = NULL;
		spin_unlock(&realm->inodes_with_caps_lock);
		ceph_put_snap_realm(mdsc, realm);
	}
	if (!__ceph_is_any_real_caps(ci))
		__cap_delay_cancel(mdsc, ci);
}

/*
 * Build and send a cap message to the given MDS.
 *
 * Caller should be holding s_mutex.
 */
static int send_cap_msg(struct ceph_mds_session *session,
			u64 ino, u64 cid, int op,
			int caps, int wanted, int dirty,
			u32 seq, u64 flush_tid, u32 issue_seq, u32 mseq,
			u64 size, u64 max_size,
			struct timespec *mtime, struct timespec *atime,
			u64 time_warp_seq,
			uid_t uid, gid_t gid, mode_t mode,
			u64 xattr_version,
			struct ceph_buffer *xattrs_buf,
			u64 follows)
{
	struct ceph_mds_caps *fc;
	struct ceph_msg *msg;

	dout("send_cap_msg %s %llx %llx caps %s wanted %s dirty %s"
	     " seq %u/%u mseq %u follows %lld size %llu/%llu"
	     " xattr_ver %llu xattr_len %d\n", ceph_cap_op_name(op),
	     cid, ino, ceph_cap_string(caps), ceph_cap_string(wanted),
	     ceph_cap_string(dirty),
	     seq, issue_seq, mseq, follows, size, max_size,
	     xattr_version, xattrs_buf ? (int)xattrs_buf->vec.iov_len : 0);

946
	msg = ceph_msg_new(CEPH_MSG_CLIENT_CAPS, sizeof(*fc), GFP_NOFS);
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	if (!msg)
		return -ENOMEM;
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	msg->hdr.tid = cpu_to_le64(flush_tid);
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	fc = msg->front.iov_base;
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	memset(fc, 0, sizeof(*fc));

	fc->cap_id = cpu_to_le64(cid);
	fc->op = cpu_to_le32(op);
	fc->seq = cpu_to_le32(seq);
	fc->issue_seq = cpu_to_le32(issue_seq);
	fc->migrate_seq = cpu_to_le32(mseq);
	fc->caps = cpu_to_le32(caps);
	fc->wanted = cpu_to_le32(wanted);
	fc->dirty = cpu_to_le32(dirty);
	fc->ino = cpu_to_le64(ino);
	fc->snap_follows = cpu_to_le64(follows);

	fc->size = cpu_to_le64(size);
	fc->max_size = cpu_to_le64(max_size);
	if (mtime)
		ceph_encode_timespec(&fc->mtime, mtime);
	if (atime)
		ceph_encode_timespec(&fc->atime, atime);
	fc->time_warp_seq = cpu_to_le32(time_warp_seq);

	fc->uid = cpu_to_le32(uid);
	fc->gid = cpu_to_le32(gid);
	fc->mode = cpu_to_le32(mode);

	fc->xattr_version = cpu_to_le64(xattr_version);
	if (xattrs_buf) {
		msg->middle = ceph_buffer_get(xattrs_buf);
		fc->xattr_len = cpu_to_le32(xattrs_buf->vec.iov_len);
		msg->hdr.middle_len = cpu_to_le32(xattrs_buf->vec.iov_len);
	}

	ceph_con_send(&session->s_con, msg);
	return 0;
}

989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028
static void __queue_cap_release(struct ceph_mds_session *session,
				u64 ino, u64 cap_id, u32 migrate_seq,
				u32 issue_seq)
{
	struct ceph_msg *msg;
	struct ceph_mds_cap_release *head;
	struct ceph_mds_cap_item *item;

	spin_lock(&session->s_cap_lock);
	BUG_ON(!session->s_num_cap_releases);
	msg = list_first_entry(&session->s_cap_releases,
			       struct ceph_msg, list_head);

	dout(" adding %llx release to mds%d msg %p (%d left)\n",
	     ino, session->s_mds, msg, session->s_num_cap_releases);

	BUG_ON(msg->front.iov_len + sizeof(*item) > PAGE_CACHE_SIZE);
	head = msg->front.iov_base;
	head->num = cpu_to_le32(le32_to_cpu(head->num) + 1);
	item = msg->front.iov_base + msg->front.iov_len;
	item->ino = cpu_to_le64(ino);
	item->cap_id = cpu_to_le64(cap_id);
	item->migrate_seq = cpu_to_le32(migrate_seq);
	item->seq = cpu_to_le32(issue_seq);

	session->s_num_cap_releases--;

	msg->front.iov_len += sizeof(*item);
	if (le32_to_cpu(head->num) == CEPH_CAPS_PER_RELEASE) {
		dout(" release msg %p full\n", msg);
		list_move_tail(&msg->list_head, &session->s_cap_releases_done);
	} else {
		dout(" release msg %p at %d/%d (%d)\n", msg,
		     (int)le32_to_cpu(head->num),
		     (int)CEPH_CAPS_PER_RELEASE,
		     (int)msg->front.iov_len);
	}
	spin_unlock(&session->s_cap_lock);
}

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/*
1030 1031
 * Queue cap releases when an inode is dropped from our cache.  Since
 * inode is about to be destroyed, there is no need for i_lock.
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 */
void ceph_queue_caps_release(struct inode *inode)
{
	struct ceph_inode_info *ci = ceph_inode(inode);
	struct rb_node *p;

	p = rb_first(&ci->i_caps);
	while (p) {
		struct ceph_cap *cap = rb_entry(p, struct ceph_cap, ci_node);
		struct ceph_mds_session *session = cap->session;

1043 1044
		__queue_cap_release(session, ceph_ino(inode), cap->cap_id,
				    cap->mseq, cap->issue_seq);
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		p = rb_next(p);
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		__ceph_remove_cap(cap);
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	}
}

/*
 * Send a cap msg on the given inode.  Update our caps state, then
 * drop i_lock and send the message.
 *
 * Make note of max_size reported/requested from mds, revoked caps
 * that have now been implemented.
 *
 * Make half-hearted attempt ot to invalidate page cache if we are
 * dropping RDCACHE.  Note that this will leave behind locked pages
 * that we'll then need to deal with elsewhere.
 *
 * Return non-zero if delayed release, or we experienced an error
 * such that the caller should requeue + retry later.
 *
 * called with i_lock, then drops it.
 * caller should hold snap_rwsem (read), s_mutex.
 */
static int __send_cap(struct ceph_mds_client *mdsc, struct ceph_cap *cap,
		      int op, int used, int want, int retain, int flushing,
		      unsigned *pflush_tid)
	__releases(cap->ci->vfs_inode->i_lock)
{
	struct ceph_inode_info *ci = cap->ci;
	struct inode *inode = &ci->vfs_inode;
	u64 cap_id = cap->cap_id;
1075
	int held, revoking, dropping, keep;
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	u64 seq, issue_seq, mseq, time_warp_seq, follows;
	u64 size, max_size;
	struct timespec mtime, atime;
	int wake = 0;
	mode_t mode;
	uid_t uid;
	gid_t gid;
	struct ceph_mds_session *session;
	u64 xattr_version = 0;
	int delayed = 0;
	u64 flush_tid = 0;
	int i;
	int ret;

1090 1091 1092 1093 1094
	held = cap->issued | cap->implemented;
	revoking = cap->implemented & ~cap->issued;
	retain &= ~revoking;
	dropping = cap->issued & ~retain;

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	dout("__send_cap %p cap %p session %p %s -> %s (revoking %s)\n",
	     inode, cap, cap->session,
	     ceph_cap_string(held), ceph_cap_string(held & retain),
	     ceph_cap_string(revoking));
	BUG_ON((retain & CEPH_CAP_PIN) == 0);

	session = cap->session;

	/* don't release wanted unless we've waited a bit. */
	if ((ci->i_ceph_flags & CEPH_I_NODELAY) == 0 &&
	    time_before(jiffies, ci->i_hold_caps_min)) {
		dout(" delaying issued %s -> %s, wanted %s -> %s on send\n",
		     ceph_cap_string(cap->issued),
		     ceph_cap_string(cap->issued & retain),
		     ceph_cap_string(cap->mds_wanted),
		     ceph_cap_string(want));
		want |= cap->mds_wanted;
		retain |= cap->issued;
		delayed = 1;
	}
	ci->i_ceph_flags &= ~(CEPH_I_NODELAY | CEPH_I_FLUSH);

	cap->issued &= retain;  /* drop bits we don't want */
	if (cap->implemented & ~cap->issued) {
		/*
		 * Wake up any waiters on wanted -> needed transition.
		 * This is due to the weird transition from buffered
		 * to sync IO... we need to flush dirty pages _before_
		 * allowing sync writes to avoid reordering.
		 */
		wake = 1;
	}
	cap->implemented &= cap->issued | used;
	cap->mds_wanted = want;

	if (flushing) {
		/*
		 * assign a tid for flush operations so we can avoid
		 * flush1 -> dirty1 -> flush2 -> flushack1 -> mark
		 * clean type races.  track latest tid for every bit
		 * so we can handle flush AxFw, flush Fw, and have the
		 * first ack clean Ax.
		 */
		flush_tid = ++ci->i_cap_flush_last_tid;
		if (pflush_tid)
			*pflush_tid = flush_tid;
		dout(" cap_flush_tid %d\n", (int)flush_tid);
		for (i = 0; i < CEPH_CAP_BITS; i++)
			if (flushing & (1 << i))
				ci->i_cap_flush_tid[i] = flush_tid;
	}

	keep = cap->implemented;
	seq = cap->seq;
	issue_seq = cap->issue_seq;
	mseq = cap->mseq;
	size = inode->i_size;
	ci->i_reported_size = size;
	max_size = ci->i_wanted_max_size;
	ci->i_requested_max_size = max_size;
	mtime = inode->i_mtime;
	atime = inode->i_atime;
	time_warp_seq = ci->i_time_warp_seq;
	follows = ci->i_snap_realm->cached_context->seq;
	uid = inode->i_uid;
	gid = inode->i_gid;
	mode = inode->i_mode;

	if (dropping & CEPH_CAP_XATTR_EXCL) {
		__ceph_build_xattrs_blob(ci);
		xattr_version = ci->i_xattrs.version + 1;
	}

	spin_unlock(&inode->i_lock);

	ret = send_cap_msg(session, ceph_vino(inode).ino, cap_id,
		op, keep, want, flushing, seq, flush_tid, issue_seq, mseq,
		size, max_size, &mtime, &atime, time_warp_seq,
		uid, gid, mode,
		xattr_version,
		(flushing & CEPH_CAP_XATTR_EXCL) ? ci->i_xattrs.blob : NULL,
		follows);
	if (ret < 0) {
		dout("error sending cap msg, must requeue %p\n", inode);
		delayed = 1;
	}

	if (wake)
1183
		wake_up_all(&ci->i_cap_wq);
S
Sage Weil 已提交
1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226

	return delayed;
}

/*
 * When a snapshot is taken, clients accumulate dirty metadata on
 * inodes with capabilities in ceph_cap_snaps to describe the file
 * state at the time the snapshot was taken.  This must be flushed
 * asynchronously back to the MDS once sync writes complete and dirty
 * data is written out.
 *
 * Called under i_lock.  Takes s_mutex as needed.
 */
void __ceph_flush_snaps(struct ceph_inode_info *ci,
			struct ceph_mds_session **psession)
{
	struct inode *inode = &ci->vfs_inode;
	int mds;
	struct ceph_cap_snap *capsnap;
	u32 mseq;
	struct ceph_mds_client *mdsc = &ceph_inode_to_client(inode)->mdsc;
	struct ceph_mds_session *session = NULL; /* if session != NULL, we hold
						    session->s_mutex */
	u64 next_follows = 0;  /* keep track of how far we've gotten through the
			     i_cap_snaps list, and skip these entries next time
			     around to avoid an infinite loop */

	if (psession)
		session = *psession;

	dout("__flush_snaps %p\n", inode);
retry:
	list_for_each_entry(capsnap, &ci->i_cap_snaps, ci_item) {
		/* avoid an infiniute loop after retry */
		if (capsnap->follows < next_follows)
			continue;
		/*
		 * we need to wait for sync writes to complete and for dirty
		 * pages to be written out.
		 */
		if (capsnap->dirty_pages || capsnap->writing)
			continue;

1227 1228 1229 1230 1231 1232
		/*
		 * if cap writeback already occurred, we should have dropped
		 * the capsnap in ceph_put_wrbuffer_cap_refs.
		 */
		BUG_ON(capsnap->dirty == 0);

S
Sage Weil 已提交
1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 1308
		/* pick mds, take s_mutex */
		mds = __ceph_get_cap_mds(ci, &mseq);
		if (session && session->s_mds != mds) {
			dout("oops, wrong session %p mutex\n", session);
			mutex_unlock(&session->s_mutex);
			ceph_put_mds_session(session);
			session = NULL;
		}
		if (!session) {
			spin_unlock(&inode->i_lock);
			mutex_lock(&mdsc->mutex);
			session = __ceph_lookup_mds_session(mdsc, mds);
			mutex_unlock(&mdsc->mutex);
			if (session) {
				dout("inverting session/ino locks on %p\n",
				     session);
				mutex_lock(&session->s_mutex);
			}
			/*
			 * if session == NULL, we raced against a cap
			 * deletion.  retry, and we'll get a better
			 * @mds value next time.
			 */
			spin_lock(&inode->i_lock);
			goto retry;
		}

		capsnap->flush_tid = ++ci->i_cap_flush_last_tid;
		atomic_inc(&capsnap->nref);
		if (!list_empty(&capsnap->flushing_item))
			list_del_init(&capsnap->flushing_item);
		list_add_tail(&capsnap->flushing_item,
			      &session->s_cap_snaps_flushing);
		spin_unlock(&inode->i_lock);

		dout("flush_snaps %p cap_snap %p follows %lld size %llu\n",
		     inode, capsnap, next_follows, capsnap->size);
		send_cap_msg(session, ceph_vino(inode).ino, 0,
			     CEPH_CAP_OP_FLUSHSNAP, capsnap->issued, 0,
			     capsnap->dirty, 0, capsnap->flush_tid, 0, mseq,
			     capsnap->size, 0,
			     &capsnap->mtime, &capsnap->atime,
			     capsnap->time_warp_seq,
			     capsnap->uid, capsnap->gid, capsnap->mode,
			     0, NULL,
			     capsnap->follows);

		next_follows = capsnap->follows + 1;
		ceph_put_cap_snap(capsnap);

		spin_lock(&inode->i_lock);
		goto retry;
	}

	/* we flushed them all; remove this inode from the queue */
	spin_lock(&mdsc->snap_flush_lock);
	list_del_init(&ci->i_snap_flush_item);
	spin_unlock(&mdsc->snap_flush_lock);

	if (psession)
		*psession = session;
	else if (session) {
		mutex_unlock(&session->s_mutex);
		ceph_put_mds_session(session);
	}
}

static void ceph_flush_snaps(struct ceph_inode_info *ci)
{
	struct inode *inode = &ci->vfs_inode;

	spin_lock(&inode->i_lock);
	__ceph_flush_snaps(ci, NULL);
	spin_unlock(&inode->i_lock);
}

S
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1309 1310 1311 1312 1313 1314
/*
 * Mark caps dirty.  If inode is newly dirty, add to the global dirty
 * list.
 */
void __ceph_mark_dirty_caps(struct ceph_inode_info *ci, int mask)
{
1315 1316
	struct ceph_mds_client *mdsc =
		&ceph_sb_to_client(ci->vfs_inode.i_sb)->mdsc;
S
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1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344
	struct inode *inode = &ci->vfs_inode;
	int was = ci->i_dirty_caps;
	int dirty = 0;

	dout("__mark_dirty_caps %p %s dirty %s -> %s\n", &ci->vfs_inode,
	     ceph_cap_string(mask), ceph_cap_string(was),
	     ceph_cap_string(was | mask));
	ci->i_dirty_caps |= mask;
	if (was == 0) {
		dout(" inode %p now dirty\n", &ci->vfs_inode);
		BUG_ON(!list_empty(&ci->i_dirty_item));
		spin_lock(&mdsc->cap_dirty_lock);
		list_add(&ci->i_dirty_item, &mdsc->cap_dirty);
		spin_unlock(&mdsc->cap_dirty_lock);
		if (ci->i_flushing_caps == 0) {
			igrab(inode);
			dirty |= I_DIRTY_SYNC;
		}
	}
	BUG_ON(list_empty(&ci->i_dirty_item));
	if (((was | ci->i_flushing_caps) & CEPH_CAP_FILE_BUFFER) &&
	    (mask & CEPH_CAP_FILE_BUFFER))
		dirty |= I_DIRTY_DATASYNC;
	if (dirty)
		__mark_inode_dirty(inode, dirty);
	__cap_delay_requeue(mdsc, ci);
}

S
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1345 1346 1347
/*
 * Add dirty inode to the flushing list.  Assigned a seq number so we
 * can wait for caps to flush without starving.
1348 1349
 *
 * Called under i_lock.
S
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1350
 */
1351
static int __mark_caps_flushing(struct inode *inode,
S
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1352 1353
				 struct ceph_mds_session *session)
{
1354
	struct ceph_mds_client *mdsc = &ceph_sb_to_client(inode->i_sb)->mdsc;
S
Sage Weil 已提交
1355
	struct ceph_inode_info *ci = ceph_inode(inode);
1356
	int flushing;
S
Sage Weil 已提交
1357

1358
	BUG_ON(ci->i_dirty_caps == 0);
S
Sage Weil 已提交
1359
	BUG_ON(list_empty(&ci->i_dirty_item));
1360 1361 1362 1363 1364 1365 1366 1367

	flushing = ci->i_dirty_caps;
	dout("__mark_caps_flushing flushing %s, flushing_caps %s -> %s\n",
	     ceph_cap_string(flushing),
	     ceph_cap_string(ci->i_flushing_caps),
	     ceph_cap_string(ci->i_flushing_caps | flushing));
	ci->i_flushing_caps |= flushing;
	ci->i_dirty_caps = 0;
1368
	dout(" inode %p now !dirty\n", inode);
1369

S
Sage Weil 已提交
1370
	spin_lock(&mdsc->cap_dirty_lock);
1371 1372 1373
	list_del_init(&ci->i_dirty_item);

	ci->i_cap_flush_seq = ++mdsc->cap_flush_seq;
S
Sage Weil 已提交
1374 1375 1376
	if (list_empty(&ci->i_flushing_item)) {
		list_add_tail(&ci->i_flushing_item, &session->s_cap_flushing);
		mdsc->num_cap_flushing++;
1377 1378 1379 1380 1381
		dout(" inode %p now flushing seq %lld\n", inode,
		     ci->i_cap_flush_seq);
	} else {
		list_move_tail(&ci->i_flushing_item, &session->s_cap_flushing);
		dout(" inode %p now flushing (more) seq %lld\n", inode,
S
Sage Weil 已提交
1382 1383 1384
		     ci->i_cap_flush_seq);
	}
	spin_unlock(&mdsc->cap_dirty_lock);
1385 1386

	return flushing;
S
Sage Weil 已提交
1387 1388
}

1389 1390 1391 1392 1393 1394 1395 1396 1397 1398 1399 1400 1401 1402 1403 1404 1405 1406 1407 1408 1409 1410 1411 1412 1413 1414 1415 1416 1417 1418 1419 1420 1421 1422 1423
/*
 * try to invalidate mapping pages without blocking.
 */
static int mapping_is_empty(struct address_space *mapping)
{
	struct page *page = find_get_page(mapping, 0);

	if (!page)
		return 1;

	put_page(page);
	return 0;
}

static int try_nonblocking_invalidate(struct inode *inode)
{
	struct ceph_inode_info *ci = ceph_inode(inode);
	u32 invalidating_gen = ci->i_rdcache_gen;

	spin_unlock(&inode->i_lock);
	invalidate_mapping_pages(&inode->i_data, 0, -1);
	spin_lock(&inode->i_lock);

	if (mapping_is_empty(&inode->i_data) &&
	    invalidating_gen == ci->i_rdcache_gen) {
		/* success. */
		dout("try_nonblocking_invalidate %p success\n", inode);
		ci->i_rdcache_gen = 0;
		ci->i_rdcache_revoking = 0;
		return 0;
	}
	dout("try_nonblocking_invalidate %p failed\n", inode);
	return -1;
}

S
Sage Weil 已提交
1424 1425 1426 1427 1428 1429 1430 1431 1432 1433 1434 1435 1436
/*
 * Swiss army knife function to examine currently used and wanted
 * versus held caps.  Release, flush, ack revoked caps to mds as
 * appropriate.
 *
 *  CHECK_CAPS_NODELAY - caller is delayed work and we should not delay
 *    cap release further.
 *  CHECK_CAPS_AUTHONLY - we should only check the auth cap
 *  CHECK_CAPS_FLUSH - we should flush any dirty caps immediately, without
 *    further delay.
 */
void ceph_check_caps(struct ceph_inode_info *ci, int flags,
		     struct ceph_mds_session *session)
1437
	__releases(session->s_mutex)
S
Sage Weil 已提交
1438 1439 1440 1441 1442 1443 1444
{
	struct ceph_client *client = ceph_inode_to_client(&ci->vfs_inode);
	struct ceph_mds_client *mdsc = &client->mdsc;
	struct inode *inode = &ci->vfs_inode;
	struct ceph_cap *cap;
	int file_wanted, used;
	int took_snap_rwsem = 0;             /* true if mdsc->snap_rwsem held */
S
Sage Weil 已提交
1445
	int issued, implemented, want, retain, revoking, flushing = 0;
S
Sage Weil 已提交
1446 1447 1448 1449 1450
	int mds = -1;   /* keep track of how far we've gone through i_caps list
			   to avoid an infinite loop on retry */
	struct rb_node *p;
	int tried_invalidate = 0;
	int delayed = 0, sent = 0, force_requeue = 0, num;
S
Sage Weil 已提交
1451
	int queue_invalidate = 0;
S
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1452 1453 1454 1455 1456 1457 1458 1459 1460 1461 1462 1463 1464 1465 1466 1467 1468 1469 1470 1471 1472
	int is_delayed = flags & CHECK_CAPS_NODELAY;

	/* if we are unmounting, flush any unused caps immediately. */
	if (mdsc->stopping)
		is_delayed = 1;

	spin_lock(&inode->i_lock);

	if (ci->i_ceph_flags & CEPH_I_FLUSH)
		flags |= CHECK_CAPS_FLUSH;

	/* flush snaps first time around only */
	if (!list_empty(&ci->i_cap_snaps))
		__ceph_flush_snaps(ci, &session);
	goto retry_locked;
retry:
	spin_lock(&inode->i_lock);
retry_locked:
	file_wanted = __ceph_caps_file_wanted(ci);
	used = __ceph_caps_used(ci);
	want = file_wanted | used;
S
Sage Weil 已提交
1473 1474
	issued = __ceph_caps_issued(ci, &implemented);
	revoking = implemented & ~issued;
S
Sage Weil 已提交
1475 1476 1477 1478 1479 1480 1481 1482 1483 1484 1485 1486 1487 1488 1489 1490 1491 1492

	retain = want | CEPH_CAP_PIN;
	if (!mdsc->stopping && inode->i_nlink > 0) {
		if (want) {
			retain |= CEPH_CAP_ANY;       /* be greedy */
		} else {
			retain |= CEPH_CAP_ANY_SHARED;
			/*
			 * keep RD only if we didn't have the file open RW,
			 * because then the mds would revoke it anyway to
			 * journal max_size=0.
			 */
			if (ci->i_max_size == 0)
				retain |= CEPH_CAP_ANY_RD;
		}
	}

	dout("check_caps %p file_want %s used %s dirty %s flushing %s"
S
Sage Weil 已提交
1493
	     " issued %s revoking %s retain %s %s%s%s\n", inode,
S
Sage Weil 已提交
1494 1495 1496
	     ceph_cap_string(file_wanted),
	     ceph_cap_string(used), ceph_cap_string(ci->i_dirty_caps),
	     ceph_cap_string(ci->i_flushing_caps),
S
Sage Weil 已提交
1497
	     ceph_cap_string(issued), ceph_cap_string(revoking),
S
Sage Weil 已提交
1498 1499 1500 1501 1502 1503 1504 1505 1506 1507 1508 1509 1510
	     ceph_cap_string(retain),
	     (flags & CHECK_CAPS_AUTHONLY) ? " AUTHONLY" : "",
	     (flags & CHECK_CAPS_NODELAY) ? " NODELAY" : "",
	     (flags & CHECK_CAPS_FLUSH) ? " FLUSH" : "");

	/*
	 * If we no longer need to hold onto old our caps, and we may
	 * have cached pages, but don't want them, then try to invalidate.
	 * If we fail, it's because pages are locked.... try again later.
	 */
	if ((!is_delayed || mdsc->stopping) &&
	    ci->i_wrbuffer_ref == 0 &&               /* no dirty pages... */
	    ci->i_rdcache_gen &&                     /* may have cached pages */
S
Sage Weil 已提交
1511
	    (file_wanted == 0 ||                     /* no open files */
1512 1513
	     (revoking & (CEPH_CAP_FILE_CACHE|
			  CEPH_CAP_FILE_LAZYIO))) && /*  or revoking cache */
S
Sage Weil 已提交
1514 1515
	    !tried_invalidate) {
		dout("check_caps trying to invalidate on %p\n", inode);
1516
		if (try_nonblocking_invalidate(inode) < 0) {
1517 1518
			if (revoking & (CEPH_CAP_FILE_CACHE|
					CEPH_CAP_FILE_LAZYIO)) {
1519 1520 1521 1522 1523 1524 1525 1526 1527 1528
				dout("check_caps queuing invalidate\n");
				queue_invalidate = 1;
				ci->i_rdcache_revoking = ci->i_rdcache_gen;
			} else {
				dout("check_caps failed to invalidate pages\n");
				/* we failed to invalidate pages.  check these
				   caps again later. */
				force_requeue = 1;
				__cap_set_timeouts(mdsc, ci);
			}
S
Sage Weil 已提交
1529 1530 1531 1532 1533 1534 1535 1536 1537 1538 1539 1540 1541 1542 1543 1544 1545 1546 1547
		}
		tried_invalidate = 1;
		goto retry_locked;
	}

	num = 0;
	for (p = rb_first(&ci->i_caps); p; p = rb_next(p)) {
		cap = rb_entry(p, struct ceph_cap, ci_node);
		num++;

		/* avoid looping forever */
		if (mds >= cap->mds ||
		    ((flags & CHECK_CAPS_AUTHONLY) && cap != ci->i_auth_cap))
			continue;

		/* NOTE: no side-effects allowed, until we take s_mutex */

		revoking = cap->implemented & ~cap->issued;
		if (revoking)
S
Sage Weil 已提交
1548
			dout(" mds%d revoking %s\n", cap->mds,
S
Sage Weil 已提交
1549 1550 1551 1552 1553 1554 1555 1556 1557 1558 1559 1560 1561 1562 1563 1564 1565 1566 1567 1568 1569 1570 1571 1572 1573 1574 1575 1576 1577 1578 1579 1580 1581 1582 1583 1584 1585 1586 1587 1588 1589 1590 1591 1592 1593 1594 1595 1596 1597 1598 1599 1600 1601 1602 1603 1604 1605
			     ceph_cap_string(revoking));

		if (cap == ci->i_auth_cap &&
		    (cap->issued & CEPH_CAP_FILE_WR)) {
			/* request larger max_size from MDS? */
			if (ci->i_wanted_max_size > ci->i_max_size &&
			    ci->i_wanted_max_size > ci->i_requested_max_size) {
				dout("requesting new max_size\n");
				goto ack;
			}

			/* approaching file_max? */
			if ((inode->i_size << 1) >= ci->i_max_size &&
			    (ci->i_reported_size << 1) < ci->i_max_size) {
				dout("i_size approaching max_size\n");
				goto ack;
			}
		}
		/* flush anything dirty? */
		if (cap == ci->i_auth_cap && (flags & CHECK_CAPS_FLUSH) &&
		    ci->i_dirty_caps) {
			dout("flushing dirty caps\n");
			goto ack;
		}

		/* completed revocation? going down and there are no caps? */
		if (revoking && (revoking & used) == 0) {
			dout("completed revocation of %s\n",
			     ceph_cap_string(cap->implemented & ~cap->issued));
			goto ack;
		}

		/* want more caps from mds? */
		if (want & ~(cap->mds_wanted | cap->issued))
			goto ack;

		/* things we might delay */
		if ((cap->issued & ~retain) == 0 &&
		    cap->mds_wanted == want)
			continue;     /* nope, all good */

		if (is_delayed)
			goto ack;

		/* delay? */
		if ((ci->i_ceph_flags & CEPH_I_NODELAY) == 0 &&
		    time_before(jiffies, ci->i_hold_caps_max)) {
			dout(" delaying issued %s -> %s, wanted %s -> %s\n",
			     ceph_cap_string(cap->issued),
			     ceph_cap_string(cap->issued & retain),
			     ceph_cap_string(cap->mds_wanted),
			     ceph_cap_string(want));
			delayed++;
			continue;
		}

ack:
1606 1607 1608 1609 1610
		if (ci->i_ceph_flags & CEPH_I_NOFLUSH) {
			dout(" skipping %p I_NOFLUSH set\n", inode);
			continue;
		}

S
Sage Weil 已提交
1611 1612 1613 1614 1615 1616 1617 1618 1619 1620 1621 1622 1623 1624 1625 1626 1627 1628 1629 1630 1631 1632 1633 1634 1635 1636 1637 1638 1639 1640 1641 1642
		if (session && session != cap->session) {
			dout("oops, wrong session %p mutex\n", session);
			mutex_unlock(&session->s_mutex);
			session = NULL;
		}
		if (!session) {
			session = cap->session;
			if (mutex_trylock(&session->s_mutex) == 0) {
				dout("inverting session/ino locks on %p\n",
				     session);
				spin_unlock(&inode->i_lock);
				if (took_snap_rwsem) {
					up_read(&mdsc->snap_rwsem);
					took_snap_rwsem = 0;
				}
				mutex_lock(&session->s_mutex);
				goto retry;
			}
		}
		/* take snap_rwsem after session mutex */
		if (!took_snap_rwsem) {
			if (down_read_trylock(&mdsc->snap_rwsem) == 0) {
				dout("inverting snap/in locks on %p\n",
				     inode);
				spin_unlock(&inode->i_lock);
				down_read(&mdsc->snap_rwsem);
				took_snap_rwsem = 1;
				goto retry;
			}
			took_snap_rwsem = 1;
		}

1643 1644
		if (cap == ci->i_auth_cap && ci->i_dirty_caps)
			flushing = __mark_caps_flushing(inode, session);
S
Sage Weil 已提交
1645 1646 1647 1648 1649 1650 1651 1652 1653 1654 1655 1656 1657 1658 1659 1660 1661 1662 1663 1664 1665 1666 1667

		mds = cap->mds;  /* remember mds, so we don't repeat */
		sent++;

		/* __send_cap drops i_lock */
		delayed += __send_cap(mdsc, cap, CEPH_CAP_OP_UPDATE, used, want,
				      retain, flushing, NULL);
		goto retry; /* retake i_lock and restart our cap scan. */
	}

	/*
	 * Reschedule delayed caps release if we delayed anything,
	 * otherwise cancel.
	 */
	if (delayed && is_delayed)
		force_requeue = 1;   /* __send_cap delayed release; requeue */
	if (!delayed && !is_delayed)
		__cap_delay_cancel(mdsc, ci);
	else if (!is_delayed || force_requeue)
		__cap_delay_requeue(mdsc, ci);

	spin_unlock(&inode->i_lock);

S
Sage Weil 已提交
1668
	if (queue_invalidate)
1669
		ceph_queue_invalidate(inode);
S
Sage Weil 已提交
1670

1671
	if (session)
S
Sage Weil 已提交
1672 1673 1674 1675 1676 1677 1678 1679 1680 1681 1682
		mutex_unlock(&session->s_mutex);
	if (took_snap_rwsem)
		up_read(&mdsc->snap_rwsem);
}

/*
 * Try to flush dirty caps back to the auth mds.
 */
static int try_flush_caps(struct inode *inode, struct ceph_mds_session *session,
			  unsigned *flush_tid)
{
1683
	struct ceph_mds_client *mdsc = &ceph_sb_to_client(inode->i_sb)->mdsc;
S
Sage Weil 已提交
1684 1685 1686 1687 1688 1689
	struct ceph_inode_info *ci = ceph_inode(inode);
	int unlock_session = session ? 0 : 1;
	int flushing = 0;

retry:
	spin_lock(&inode->i_lock);
1690 1691 1692 1693
	if (ci->i_ceph_flags & CEPH_I_NOFLUSH) {
		dout("try_flush_caps skipping %p I_NOFLUSH set\n", inode);
		goto out;
	}
S
Sage Weil 已提交
1694 1695 1696 1697 1698 1699 1700 1701 1702 1703 1704 1705 1706 1707 1708 1709
	if (ci->i_dirty_caps && ci->i_auth_cap) {
		struct ceph_cap *cap = ci->i_auth_cap;
		int used = __ceph_caps_used(ci);
		int want = __ceph_caps_wanted(ci);
		int delayed;

		if (!session) {
			spin_unlock(&inode->i_lock);
			session = cap->session;
			mutex_lock(&session->s_mutex);
			goto retry;
		}
		BUG_ON(session != cap->session);
		if (cap->session->s_state < CEPH_MDS_SESSION_OPEN)
			goto out;

1710
		flushing = __mark_caps_flushing(inode, session);
S
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1711 1712 1713 1714 1715 1716 1717 1718 1719 1720 1721 1722 1723 1724 1725 1726 1727 1728 1729 1730 1731 1732 1733 1734 1735

		/* __send_cap drops i_lock */
		delayed = __send_cap(mdsc, cap, CEPH_CAP_OP_FLUSH, used, want,
				     cap->issued | cap->implemented, flushing,
				     flush_tid);
		if (!delayed)
			goto out_unlocked;

		spin_lock(&inode->i_lock);
		__cap_delay_requeue(mdsc, ci);
	}
out:
	spin_unlock(&inode->i_lock);
out_unlocked:
	if (session && unlock_session)
		mutex_unlock(&session->s_mutex);
	return flushing;
}

/*
 * Return true if we've flushed caps through the given flush_tid.
 */
static int caps_are_flushed(struct inode *inode, unsigned tid)
{
	struct ceph_inode_info *ci = ceph_inode(inode);
1736
	int i, ret = 1;
S
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1737 1738 1739 1740 1741 1742 1743 1744 1745 1746 1747 1748 1749 1750 1751 1752 1753 1754 1755 1756 1757 1758 1759 1760 1761 1762 1763 1764 1765 1766 1767 1768 1769 1770 1771 1772 1773 1774 1775 1776 1777 1778 1779 1780 1781 1782 1783 1784 1785 1786 1787 1788 1789 1790 1791 1792 1793

	spin_lock(&inode->i_lock);
	for (i = 0; i < CEPH_CAP_BITS; i++)
		if ((ci->i_flushing_caps & (1 << i)) &&
		    ci->i_cap_flush_tid[i] <= tid) {
			/* still flushing this bit */
			ret = 0;
			break;
		}
	spin_unlock(&inode->i_lock);
	return ret;
}

/*
 * Wait on any unsafe replies for the given inode.  First wait on the
 * newest request, and make that the upper bound.  Then, if there are
 * more requests, keep waiting on the oldest as long as it is still older
 * than the original request.
 */
static void sync_write_wait(struct inode *inode)
{
	struct ceph_inode_info *ci = ceph_inode(inode);
	struct list_head *head = &ci->i_unsafe_writes;
	struct ceph_osd_request *req;
	u64 last_tid;

	spin_lock(&ci->i_unsafe_lock);
	if (list_empty(head))
		goto out;

	/* set upper bound as _last_ entry in chain */
	req = list_entry(head->prev, struct ceph_osd_request,
			 r_unsafe_item);
	last_tid = req->r_tid;

	do {
		ceph_osdc_get_request(req);
		spin_unlock(&ci->i_unsafe_lock);
		dout("sync_write_wait on tid %llu (until %llu)\n",
		     req->r_tid, last_tid);
		wait_for_completion(&req->r_safe_completion);
		spin_lock(&ci->i_unsafe_lock);
		ceph_osdc_put_request(req);

		/*
		 * from here on look at first entry in chain, since we
		 * only want to wait for anything older than last_tid
		 */
		if (list_empty(head))
			break;
		req = list_entry(head->next, struct ceph_osd_request,
				 r_unsafe_item);
	} while (req->r_tid < last_tid);
out:
	spin_unlock(&ci->i_unsafe_lock);
}

1794
int ceph_fsync(struct file *file, int datasync)
S
Sage Weil 已提交
1795
{
1796
	struct inode *inode = file->f_mapping->host;
S
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1797 1798 1799 1800 1801 1802 1803 1804 1805 1806 1807 1808 1809 1810 1811 1812 1813 1814 1815 1816 1817 1818 1819 1820 1821 1822 1823 1824 1825 1826 1827 1828 1829 1830 1831 1832
	struct ceph_inode_info *ci = ceph_inode(inode);
	unsigned flush_tid;
	int ret;
	int dirty;

	dout("fsync %p%s\n", inode, datasync ? " datasync" : "");
	sync_write_wait(inode);

	ret = filemap_write_and_wait(inode->i_mapping);
	if (ret < 0)
		return ret;

	dirty = try_flush_caps(inode, NULL, &flush_tid);
	dout("fsync dirty caps are %s\n", ceph_cap_string(dirty));

	/*
	 * only wait on non-file metadata writeback (the mds
	 * can recover size and mtime, so we don't need to
	 * wait for that)
	 */
	if (!datasync && (dirty & ~CEPH_CAP_ANY_FILE_WR)) {
		dout("fsync waiting for flush_tid %u\n", flush_tid);
		ret = wait_event_interruptible(ci->i_cap_wq,
				       caps_are_flushed(inode, flush_tid));
	}

	dout("fsync %p%s done\n", inode, datasync ? " datasync" : "");
	return ret;
}

/*
 * Flush any dirty caps back to the mds.  If we aren't asked to wait,
 * queue inode for flush but don't do so immediately, because we can
 * get by with fewer MDS messages if we wait for data writeback to
 * complete first.
 */
1833
int ceph_write_inode(struct inode *inode, struct writeback_control *wbc)
S
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1834 1835 1836 1837 1838
{
	struct ceph_inode_info *ci = ceph_inode(inode);
	unsigned flush_tid;
	int err = 0;
	int dirty;
1839
	int wait = wbc->sync_mode == WB_SYNC_ALL;
S
Sage Weil 已提交
1840 1841 1842 1843 1844 1845 1846 1847

	dout("write_inode %p wait=%d\n", inode, wait);
	if (wait) {
		dirty = try_flush_caps(inode, NULL, &flush_tid);
		if (dirty)
			err = wait_event_interruptible(ci->i_cap_wq,
				       caps_are_flushed(inode, flush_tid));
	} else {
1848 1849
		struct ceph_mds_client *mdsc =
			&ceph_sb_to_client(inode->i_sb)->mdsc;
S
Sage Weil 已提交
1850 1851 1852 1853 1854 1855 1856 1857 1858 1859 1860 1861 1862 1863 1864 1865 1866 1867 1868 1869 1870 1871 1872 1873 1874 1875 1876 1877 1878 1879 1880 1881 1882 1883 1884 1885 1886

		spin_lock(&inode->i_lock);
		if (__ceph_caps_dirty(ci))
			__cap_delay_requeue_front(mdsc, ci);
		spin_unlock(&inode->i_lock);
	}
	return err;
}

/*
 * After a recovering MDS goes active, we need to resend any caps
 * we were flushing.
 *
 * Caller holds session->s_mutex.
 */
static void kick_flushing_capsnaps(struct ceph_mds_client *mdsc,
				   struct ceph_mds_session *session)
{
	struct ceph_cap_snap *capsnap;

	dout("kick_flushing_capsnaps mds%d\n", session->s_mds);
	list_for_each_entry(capsnap, &session->s_cap_snaps_flushing,
			    flushing_item) {
		struct ceph_inode_info *ci = capsnap->ci;
		struct inode *inode = &ci->vfs_inode;
		struct ceph_cap *cap;

		spin_lock(&inode->i_lock);
		cap = ci->i_auth_cap;
		if (cap && cap->session == session) {
			dout("kick_flushing_caps %p cap %p capsnap %p\n", inode,
			     cap, capsnap);
			__ceph_flush_snaps(ci, &session);
		} else {
			pr_err("%p auth cap %p not mds%d ???\n", inode,
			       cap, session->s_mds);
		}
1887
		spin_unlock(&inode->i_lock);
S
Sage Weil 已提交
1888 1889 1890 1891 1892 1893 1894 1895 1896 1897 1898 1899 1900 1901 1902 1903 1904 1905 1906 1907 1908 1909 1910 1911 1912 1913 1914 1915 1916 1917 1918 1919 1920 1921 1922 1923 1924 1925 1926 1927 1928 1929 1930 1931 1932 1933 1934 1935 1936 1937 1938 1939 1940 1941 1942 1943 1944 1945 1946 1947 1948 1949 1950 1951 1952 1953 1954 1955 1956 1957 1958 1959 1960 1961 1962 1963 1964 1965
	}
}

void ceph_kick_flushing_caps(struct ceph_mds_client *mdsc,
			     struct ceph_mds_session *session)
{
	struct ceph_inode_info *ci;

	kick_flushing_capsnaps(mdsc, session);

	dout("kick_flushing_caps mds%d\n", session->s_mds);
	list_for_each_entry(ci, &session->s_cap_flushing, i_flushing_item) {
		struct inode *inode = &ci->vfs_inode;
		struct ceph_cap *cap;
		int delayed = 0;

		spin_lock(&inode->i_lock);
		cap = ci->i_auth_cap;
		if (cap && cap->session == session) {
			dout("kick_flushing_caps %p cap %p %s\n", inode,
			     cap, ceph_cap_string(ci->i_flushing_caps));
			delayed = __send_cap(mdsc, cap, CEPH_CAP_OP_FLUSH,
					     __ceph_caps_used(ci),
					     __ceph_caps_wanted(ci),
					     cap->issued | cap->implemented,
					     ci->i_flushing_caps, NULL);
			if (delayed) {
				spin_lock(&inode->i_lock);
				__cap_delay_requeue(mdsc, ci);
				spin_unlock(&inode->i_lock);
			}
		} else {
			pr_err("%p auth cap %p not mds%d ???\n", inode,
			       cap, session->s_mds);
			spin_unlock(&inode->i_lock);
		}
	}
}


/*
 * Take references to capabilities we hold, so that we don't release
 * them to the MDS prematurely.
 *
 * Protected by i_lock.
 */
static void __take_cap_refs(struct ceph_inode_info *ci, int got)
{
	if (got & CEPH_CAP_PIN)
		ci->i_pin_ref++;
	if (got & CEPH_CAP_FILE_RD)
		ci->i_rd_ref++;
	if (got & CEPH_CAP_FILE_CACHE)
		ci->i_rdcache_ref++;
	if (got & CEPH_CAP_FILE_WR)
		ci->i_wr_ref++;
	if (got & CEPH_CAP_FILE_BUFFER) {
		if (ci->i_wrbuffer_ref == 0)
			igrab(&ci->vfs_inode);
		ci->i_wrbuffer_ref++;
		dout("__take_cap_refs %p wrbuffer %d -> %d (?)\n",
		     &ci->vfs_inode, ci->i_wrbuffer_ref-1, ci->i_wrbuffer_ref);
	}
}

/*
 * Try to grab cap references.  Specify those refs we @want, and the
 * minimal set we @need.  Also include the larger offset we are writing
 * to (when applicable), and check against max_size here as well.
 * Note that caller is responsible for ensuring max_size increases are
 * requested from the MDS.
 */
static int try_get_cap_refs(struct ceph_inode_info *ci, int need, int want,
			    int *got, loff_t endoff, int *check_max, int *err)
{
	struct inode *inode = &ci->vfs_inode;
	int ret = 0;
	int have, implemented;
1966
	int file_wanted;
S
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1967 1968 1969 1970 1971

	dout("get_cap_refs %p need %s want %s\n", inode,
	     ceph_cap_string(need), ceph_cap_string(want));
	spin_lock(&inode->i_lock);

1972 1973 1974 1975 1976
	/* make sure file is actually open */
	file_wanted = __ceph_caps_file_wanted(ci);
	if ((file_wanted & need) == 0) {
		dout("try_get_cap_refs need %s file_wanted %s, EBADF\n",
		     ceph_cap_string(need), ceph_cap_string(file_wanted));
S
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1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033 2034 2035 2036 2037 2038 2039 2040 2041 2042 2043 2044 2045 2046 2047 2048 2049 2050 2051 2052 2053 2054 2055 2056 2057 2058 2059 2060 2061 2062 2063 2064 2065 2066 2067 2068 2069 2070 2071 2072 2073 2074 2075 2076 2077 2078 2079 2080 2081 2082 2083 2084 2085 2086 2087 2088 2089 2090 2091 2092 2093 2094 2095 2096 2097 2098 2099 2100 2101 2102 2103 2104 2105 2106 2107 2108 2109 2110 2111 2112 2113 2114 2115 2116 2117 2118 2119 2120 2121 2122 2123 2124 2125 2126 2127 2128 2129 2130 2131 2132 2133 2134 2135 2136 2137 2138 2139 2140 2141 2142 2143 2144 2145 2146 2147 2148
		*err = -EBADF;
		ret = 1;
		goto out;
	}

	if (need & CEPH_CAP_FILE_WR) {
		if (endoff >= 0 && endoff > (loff_t)ci->i_max_size) {
			dout("get_cap_refs %p endoff %llu > maxsize %llu\n",
			     inode, endoff, ci->i_max_size);
			if (endoff > ci->i_wanted_max_size) {
				*check_max = 1;
				ret = 1;
			}
			goto out;
		}
		/*
		 * If a sync write is in progress, we must wait, so that we
		 * can get a final snapshot value for size+mtime.
		 */
		if (__ceph_have_pending_cap_snap(ci)) {
			dout("get_cap_refs %p cap_snap_pending\n", inode);
			goto out;
		}
	}
	have = __ceph_caps_issued(ci, &implemented);

	/*
	 * disallow writes while a truncate is pending
	 */
	if (ci->i_truncate_pending)
		have &= ~CEPH_CAP_FILE_WR;

	if ((have & need) == need) {
		/*
		 * Look at (implemented & ~have & not) so that we keep waiting
		 * on transition from wanted -> needed caps.  This is needed
		 * for WRBUFFER|WR -> WR to avoid a new WR sync write from
		 * going before a prior buffered writeback happens.
		 */
		int not = want & ~(have & need);
		int revoking = implemented & ~have;
		dout("get_cap_refs %p have %s but not %s (revoking %s)\n",
		     inode, ceph_cap_string(have), ceph_cap_string(not),
		     ceph_cap_string(revoking));
		if ((revoking & not) == 0) {
			*got = need | (have & want);
			__take_cap_refs(ci, *got);
			ret = 1;
		}
	} else {
		dout("get_cap_refs %p have %s needed %s\n", inode,
		     ceph_cap_string(have), ceph_cap_string(need));
	}
out:
	spin_unlock(&inode->i_lock);
	dout("get_cap_refs %p ret %d got %s\n", inode,
	     ret, ceph_cap_string(*got));
	return ret;
}

/*
 * Check the offset we are writing up to against our current
 * max_size.  If necessary, tell the MDS we want to write to
 * a larger offset.
 */
static void check_max_size(struct inode *inode, loff_t endoff)
{
	struct ceph_inode_info *ci = ceph_inode(inode);
	int check = 0;

	/* do we need to explicitly request a larger max_size? */
	spin_lock(&inode->i_lock);
	if ((endoff >= ci->i_max_size ||
	     endoff > (inode->i_size << 1)) &&
	    endoff > ci->i_wanted_max_size) {
		dout("write %p at large endoff %llu, req max_size\n",
		     inode, endoff);
		ci->i_wanted_max_size = endoff;
		check = 1;
	}
	spin_unlock(&inode->i_lock);
	if (check)
		ceph_check_caps(ci, CHECK_CAPS_AUTHONLY, NULL);
}

/*
 * Wait for caps, and take cap references.  If we can't get a WR cap
 * due to a small max_size, make sure we check_max_size (and possibly
 * ask the mds) so we don't get hung up indefinitely.
 */
int ceph_get_caps(struct ceph_inode_info *ci, int need, int want, int *got,
		  loff_t endoff)
{
	int check_max, ret, err;

retry:
	if (endoff > 0)
		check_max_size(&ci->vfs_inode, endoff);
	check_max = 0;
	err = 0;
	ret = wait_event_interruptible(ci->i_cap_wq,
				       try_get_cap_refs(ci, need, want,
							got, endoff,
							&check_max, &err));
	if (err)
		ret = err;
	if (check_max)
		goto retry;
	return ret;
}

/*
 * Take cap refs.  Caller must already know we hold at least one ref
 * on the caps in question or we don't know this is safe.
 */
void ceph_get_cap_refs(struct ceph_inode_info *ci, int caps)
{
	spin_lock(&ci->vfs_inode.i_lock);
	__take_cap_refs(ci, caps);
	spin_unlock(&ci->vfs_inode.i_lock);
}

/*
 * Release cap refs.
 *
 * If we released the last ref on any given cap, call ceph_check_caps
 * to release (or schedule a release).
 *
 * If we are releasing a WR cap (from a sync write), finalize any affected
 * cap_snap, and wake up any waiters.
 */
void ceph_put_cap_refs(struct ceph_inode_info *ci, int had)
{
	struct inode *inode = &ci->vfs_inode;
	int last = 0, put = 0, flushsnaps = 0, wake = 0;
	struct ceph_cap_snap *capsnap;

	spin_lock(&inode->i_lock);
	if (had & CEPH_CAP_PIN)
		--ci->i_pin_ref;
	if (had & CEPH_CAP_FILE_RD)
		if (--ci->i_rd_ref == 0)
			last++;
	if (had & CEPH_CAP_FILE_CACHE)
		if (--ci->i_rdcache_ref == 0)
			last++;
	if (had & CEPH_CAP_FILE_BUFFER) {
		if (--ci->i_wrbuffer_ref == 0) {
			last++;
			put++;
		}
		dout("put_cap_refs %p wrbuffer %d -> %d (?)\n",
		     inode, ci->i_wrbuffer_ref+1, ci->i_wrbuffer_ref);
	}
	if (had & CEPH_CAP_FILE_WR)
		if (--ci->i_wr_ref == 0) {
			last++;
			if (!list_empty(&ci->i_cap_snaps)) {
				capsnap = list_first_entry(&ci->i_cap_snaps,
						     struct ceph_cap_snap,
						     ci_item);
				if (capsnap->writing) {
					capsnap->writing = 0;
					flushsnaps =
						__ceph_finish_cap_snap(ci,
								       capsnap);
					wake = 1;
				}
			}
		}
	spin_unlock(&inode->i_lock);

2149 2150
	dout("put_cap_refs %p had %s%s%s\n", inode, ceph_cap_string(had),
	     last ? " last" : "", put ? " put" : "");
S
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2151 2152 2153 2154 2155 2156

	if (last && !flushsnaps)
		ceph_check_caps(ci, 0, NULL);
	else if (flushsnaps)
		ceph_flush_snaps(ci);
	if (wake)
2157
		wake_up_all(&ci->i_cap_wq);
S
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2158 2159 2160 2161 2162 2163 2164 2165 2166 2167 2168 2169 2170 2171 2172 2173
	if (put)
		iput(inode);
}

/*
 * Release @nr WRBUFFER refs on dirty pages for the given @snapc snap
 * context.  Adjust per-snap dirty page accounting as appropriate.
 * Once all dirty data for a cap_snap is flushed, flush snapped file
 * metadata back to the MDS.  If we dropped the last ref, call
 * ceph_check_caps.
 */
void ceph_put_wrbuffer_cap_refs(struct ceph_inode_info *ci, int nr,
				struct ceph_snap_context *snapc)
{
	struct inode *inode = &ci->vfs_inode;
	int last = 0;
2174 2175
	int complete_capsnap = 0;
	int drop_capsnap = 0;
S
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2176 2177 2178 2179 2180 2181 2182 2183 2184 2185 2186 2187 2188 2189 2190 2191 2192 2193 2194 2195 2196 2197 2198 2199 2200 2201
	int found = 0;
	struct ceph_cap_snap *capsnap = NULL;

	spin_lock(&inode->i_lock);
	ci->i_wrbuffer_ref -= nr;
	last = !ci->i_wrbuffer_ref;

	if (ci->i_head_snapc == snapc) {
		ci->i_wrbuffer_ref_head -= nr;
		if (!ci->i_wrbuffer_ref_head) {
			ceph_put_snap_context(ci->i_head_snapc);
			ci->i_head_snapc = NULL;
		}
		dout("put_wrbuffer_cap_refs on %p head %d/%d -> %d/%d %s\n",
		     inode,
		     ci->i_wrbuffer_ref+nr, ci->i_wrbuffer_ref_head+nr,
		     ci->i_wrbuffer_ref, ci->i_wrbuffer_ref_head,
		     last ? " LAST" : "");
	} else {
		list_for_each_entry(capsnap, &ci->i_cap_snaps, ci_item) {
			if (capsnap->context == snapc) {
				found = 1;
				break;
			}
		}
		BUG_ON(!found);
2202 2203 2204 2205 2206 2207 2208 2209
		capsnap->dirty_pages -= nr;
		if (capsnap->dirty_pages == 0) {
			complete_capsnap = 1;
			if (capsnap->dirty == 0)
				/* cap writeback completed before we created
				 * the cap_snap; no FLUSHSNAP is needed */
				drop_capsnap = 1;
		}
S
Sage Weil 已提交
2210
		dout("put_wrbuffer_cap_refs on %p cap_snap %p "
2211
		     " snap %lld %d/%d -> %d/%d %s%s%s\n",
S
Sage Weil 已提交
2212 2213 2214 2215
		     inode, capsnap, capsnap->context->seq,
		     ci->i_wrbuffer_ref+nr, capsnap->dirty_pages + nr,
		     ci->i_wrbuffer_ref, capsnap->dirty_pages,
		     last ? " (wrbuffer last)" : "",
2216 2217 2218 2219 2220 2221 2222 2223
		     complete_capsnap ? " (complete capsnap)" : "",
		     drop_capsnap ? " (drop capsnap)" : "");
		if (drop_capsnap) {
			ceph_put_snap_context(capsnap->context);
			list_del(&capsnap->ci_item);
			list_del(&capsnap->flushing_item);
			ceph_put_cap_snap(capsnap);
		}
S
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2224 2225 2226 2227 2228 2229 2230
	}

	spin_unlock(&inode->i_lock);

	if (last) {
		ceph_check_caps(ci, CHECK_CAPS_AUTHONLY, NULL);
		iput(inode);
2231
	} else if (complete_capsnap) {
S
Sage Weil 已提交
2232
		ceph_flush_snaps(ci);
2233
		wake_up_all(&ci->i_cap_wq);
S
Sage Weil 已提交
2234
	}
2235 2236
	if (drop_capsnap)
		iput(inode);
S
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2237 2238 2239 2240 2241 2242
}

/*
 * Handle a cap GRANT message from the MDS.  (Note that a GRANT may
 * actually be a revocation if it specifies a smaller cap set.)
 *
2243 2244
 * caller holds s_mutex and i_lock, we drop both.
 *
S
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2245 2246 2247 2248 2249
 * return value:
 *  0 - ok
 *  1 - check_caps on auth cap only (writeback)
 *  2 - check_caps (ack revoke)
 */
2250 2251 2252 2253
static void handle_cap_grant(struct inode *inode, struct ceph_mds_caps *grant,
			     struct ceph_mds_session *session,
			     struct ceph_cap *cap,
			     struct ceph_buffer *xattr_buf)
S
Sage Weil 已提交
2254
	__releases(inode->i_lock)
2255
	__releases(session->s_mutex)
S
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2256 2257 2258 2259 2260 2261 2262 2263 2264
{
	struct ceph_inode_info *ci = ceph_inode(inode);
	int mds = session->s_mds;
	int seq = le32_to_cpu(grant->seq);
	int newcaps = le32_to_cpu(grant->caps);
	int issued, implemented, used, wanted, dirty;
	u64 size = le64_to_cpu(grant->size);
	u64 max_size = le64_to_cpu(grant->max_size);
	struct timespec mtime, atime, ctime;
2265
	int check_caps = 0;
S
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2266 2267 2268
	int wake = 0;
	int writeback = 0;
	int revoked_rdcache = 0;
2269
	int queue_invalidate = 0;
S
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2270 2271 2272 2273 2274 2275 2276 2277 2278 2279 2280

	dout("handle_cap_grant inode %p cap %p mds%d seq %d %s\n",
	     inode, cap, mds, seq, ceph_cap_string(newcaps));
	dout(" size %llu max_size %llu, i_size %llu\n", size, max_size,
		inode->i_size);

	/*
	 * If CACHE is being revoked, and we have no dirty buffers,
	 * try to invalidate (once).  (If there are dirty buffers, we
	 * will invalidate _after_ writeback.)
	 */
2281 2282
	if (((cap->issued & ~newcaps) & (CEPH_CAP_FILE_CACHE|
					 CEPH_CAP_FILE_LAZYIO)) &&
2283
	    !ci->i_wrbuffer_ref) {
2284 2285 2286
		if (try_nonblocking_invalidate(inode) == 0) {
			revoked_rdcache = 1;
		} else {
S
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2287 2288 2289
			/* there were locked pages.. invalidate later
			   in a separate thread. */
			if (ci->i_rdcache_revoking != ci->i_rdcache_gen) {
2290
				queue_invalidate = 1;
S
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2291 2292 2293 2294 2295 2296 2297 2298 2299 2300
				ci->i_rdcache_revoking = ci->i_rdcache_gen;
			}
		}
	}

	/* side effects now are allowed */

	issued = __ceph_caps_issued(ci, &implemented);
	issued |= implemented | __ceph_caps_dirty(ci);

2301
	cap->cap_gen = session->s_cap_gen;
S
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2302 2303 2304 2305 2306 2307 2308 2309 2310 2311 2312 2313 2314 2315 2316 2317 2318 2319 2320 2321 2322 2323 2324 2325 2326 2327 2328 2329 2330 2331 2332 2333 2334 2335 2336 2337 2338 2339 2340 2341 2342 2343 2344 2345 2346 2347 2348 2349 2350 2351 2352 2353 2354 2355 2356 2357 2358 2359 2360 2361 2362 2363 2364 2365 2366 2367 2368 2369 2370 2371 2372 2373 2374 2375 2376 2377 2378

	__check_cap_issue(ci, cap, newcaps);

	if ((issued & CEPH_CAP_AUTH_EXCL) == 0) {
		inode->i_mode = le32_to_cpu(grant->mode);
		inode->i_uid = le32_to_cpu(grant->uid);
		inode->i_gid = le32_to_cpu(grant->gid);
		dout("%p mode 0%o uid.gid %d.%d\n", inode, inode->i_mode,
		     inode->i_uid, inode->i_gid);
	}

	if ((issued & CEPH_CAP_LINK_EXCL) == 0)
		inode->i_nlink = le32_to_cpu(grant->nlink);

	if ((issued & CEPH_CAP_XATTR_EXCL) == 0 && grant->xattr_len) {
		int len = le32_to_cpu(grant->xattr_len);
		u64 version = le64_to_cpu(grant->xattr_version);

		if (version > ci->i_xattrs.version) {
			dout(" got new xattrs v%llu on %p len %d\n",
			     version, inode, len);
			if (ci->i_xattrs.blob)
				ceph_buffer_put(ci->i_xattrs.blob);
			ci->i_xattrs.blob = ceph_buffer_get(xattr_buf);
			ci->i_xattrs.version = version;
		}
	}

	/* size/ctime/mtime/atime? */
	ceph_fill_file_size(inode, issued,
			    le32_to_cpu(grant->truncate_seq),
			    le64_to_cpu(grant->truncate_size), size);
	ceph_decode_timespec(&mtime, &grant->mtime);
	ceph_decode_timespec(&atime, &grant->atime);
	ceph_decode_timespec(&ctime, &grant->ctime);
	ceph_fill_file_time(inode, issued,
			    le32_to_cpu(grant->time_warp_seq), &ctime, &mtime,
			    &atime);

	/* max size increase? */
	if (max_size != ci->i_max_size) {
		dout("max_size %lld -> %llu\n", ci->i_max_size, max_size);
		ci->i_max_size = max_size;
		if (max_size >= ci->i_wanted_max_size) {
			ci->i_wanted_max_size = 0;  /* reset */
			ci->i_requested_max_size = 0;
		}
		wake = 1;
	}

	/* check cap bits */
	wanted = __ceph_caps_wanted(ci);
	used = __ceph_caps_used(ci);
	dirty = __ceph_caps_dirty(ci);
	dout(" my wanted = %s, used = %s, dirty %s\n",
	     ceph_cap_string(wanted),
	     ceph_cap_string(used),
	     ceph_cap_string(dirty));
	if (wanted != le32_to_cpu(grant->wanted)) {
		dout("mds wanted %s -> %s\n",
		     ceph_cap_string(le32_to_cpu(grant->wanted)),
		     ceph_cap_string(wanted));
		grant->wanted = cpu_to_le32(wanted);
	}

	cap->seq = seq;

	/* file layout may have changed */
	ci->i_layout = grant->layout;

	/* revocation, grant, or no-op? */
	if (cap->issued & ~newcaps) {
		dout("revocation: %s -> %s\n", ceph_cap_string(cap->issued),
		     ceph_cap_string(newcaps));
		if ((used & ~newcaps) & CEPH_CAP_FILE_BUFFER)
			writeback = 1; /* will delay ack */
		else if (dirty & ~newcaps)
2379
			check_caps = 1;  /* initiate writeback in check_caps */
2380 2381
		else if (((used & ~newcaps) & (CEPH_CAP_FILE_CACHE|
					       CEPH_CAP_FILE_LAZYIO)) == 0 ||
S
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2382
			   revoked_rdcache)
2383
			check_caps = 2;     /* send revoke ack in check_caps */
S
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2384
		cap->issued = newcaps;
2385
		cap->implemented |= newcaps;
S
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2386 2387 2388 2389 2390 2391 2392 2393 2394 2395 2396 2397
	} else if (cap->issued == newcaps) {
		dout("caps unchanged: %s -> %s\n",
		     ceph_cap_string(cap->issued), ceph_cap_string(newcaps));
	} else {
		dout("grant: %s -> %s\n", ceph_cap_string(cap->issued),
		     ceph_cap_string(newcaps));
		cap->issued = newcaps;
		cap->implemented |= newcaps; /* add bits only, to
					      * avoid stepping on a
					      * pending revocation */
		wake = 1;
	}
2398
	BUG_ON(cap->issued & ~cap->implemented);
S
Sage Weil 已提交
2399 2400

	spin_unlock(&inode->i_lock);
2401
	if (writeback)
S
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2402 2403 2404 2405 2406
		/*
		 * queue inode for writeback: we can't actually call
		 * filemap_write_and_wait, etc. from message handler
		 * context.
		 */
2407 2408 2409
		ceph_queue_writeback(inode);
	if (queue_invalidate)
		ceph_queue_invalidate(inode);
S
Sage Weil 已提交
2410
	if (wake)
2411
		wake_up_all(&ci->i_cap_wq);
2412 2413 2414 2415 2416 2417 2418 2419

	if (check_caps == 1)
		ceph_check_caps(ci, CHECK_CAPS_NODELAY|CHECK_CAPS_AUTHONLY,
				session);
	else if (check_caps == 2)
		ceph_check_caps(ci, CHECK_CAPS_NODELAY, session);
	else
		mutex_unlock(&session->s_mutex);
S
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2420 2421 2422 2423 2424 2425
}

/*
 * Handle FLUSH_ACK from MDS, indicating that metadata we sent to the
 * MDS has been safely committed.
 */
2426
static void handle_cap_flush_ack(struct inode *inode, u64 flush_tid,
S
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2427 2428 2429 2430 2431 2432
				 struct ceph_mds_caps *m,
				 struct ceph_mds_session *session,
				 struct ceph_cap *cap)
	__releases(inode->i_lock)
{
	struct ceph_inode_info *ci = ceph_inode(inode);
2433
	struct ceph_mds_client *mdsc = &ceph_sb_to_client(inode->i_sb)->mdsc;
S
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2434 2435 2436
	unsigned seq = le32_to_cpu(m->seq);
	int dirty = le32_to_cpu(m->dirty);
	int cleaned = 0;
2437
	int drop = 0;
S
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2438 2439 2440 2441 2442 2443 2444 2445 2446 2447 2448 2449 2450 2451 2452 2453 2454 2455 2456 2457 2458 2459 2460 2461 2462 2463 2464 2465
	int i;

	for (i = 0; i < CEPH_CAP_BITS; i++)
		if ((dirty & (1 << i)) &&
		    flush_tid == ci->i_cap_flush_tid[i])
			cleaned |= 1 << i;

	dout("handle_cap_flush_ack inode %p mds%d seq %d on %s cleaned %s,"
	     " flushing %s -> %s\n",
	     inode, session->s_mds, seq, ceph_cap_string(dirty),
	     ceph_cap_string(cleaned), ceph_cap_string(ci->i_flushing_caps),
	     ceph_cap_string(ci->i_flushing_caps & ~cleaned));

	if (ci->i_flushing_caps == (ci->i_flushing_caps & ~cleaned))
		goto out;

	ci->i_flushing_caps &= ~cleaned;

	spin_lock(&mdsc->cap_dirty_lock);
	if (ci->i_flushing_caps == 0) {
		list_del_init(&ci->i_flushing_item);
		if (!list_empty(&session->s_cap_flushing))
			dout(" mds%d still flushing cap on %p\n",
			     session->s_mds,
			     &list_entry(session->s_cap_flushing.next,
					 struct ceph_inode_info,
					 i_flushing_item)->vfs_inode);
		mdsc->num_cap_flushing--;
2466
		wake_up_all(&mdsc->cap_flushing_wq);
S
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2467
		dout(" inode %p now !flushing\n", inode);
2468 2469 2470 2471 2472

		if (ci->i_dirty_caps == 0) {
			dout(" inode %p now clean\n", inode);
			BUG_ON(!list_empty(&ci->i_dirty_item));
			drop = 1;
S
Sage Weil 已提交
2473 2474
		} else {
			BUG_ON(list_empty(&ci->i_dirty_item));
2475
		}
S
Sage Weil 已提交
2476 2477
	}
	spin_unlock(&mdsc->cap_dirty_lock);
2478
	wake_up_all(&ci->i_cap_wq);
S
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2479 2480 2481

out:
	spin_unlock(&inode->i_lock);
2482
	if (drop)
S
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2483 2484 2485 2486 2487 2488 2489 2490 2491
		iput(inode);
}

/*
 * Handle FLUSHSNAP_ACK.  MDS has flushed snap data to disk and we can
 * throw away our cap_snap.
 *
 * Caller hold s_mutex.
 */
2492
static void handle_cap_flushsnap_ack(struct inode *inode, u64 flush_tid,
S
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2493 2494 2495 2496 2497 2498 2499 2500 2501 2502 2503 2504 2505 2506 2507 2508 2509 2510 2511 2512 2513
				     struct ceph_mds_caps *m,
				     struct ceph_mds_session *session)
{
	struct ceph_inode_info *ci = ceph_inode(inode);
	u64 follows = le64_to_cpu(m->snap_follows);
	struct ceph_cap_snap *capsnap;
	int drop = 0;

	dout("handle_cap_flushsnap_ack inode %p ci %p mds%d follows %lld\n",
	     inode, ci, session->s_mds, follows);

	spin_lock(&inode->i_lock);
	list_for_each_entry(capsnap, &ci->i_cap_snaps, ci_item) {
		if (capsnap->follows == follows) {
			if (capsnap->flush_tid != flush_tid) {
				dout(" cap_snap %p follows %lld tid %lld !="
				     " %lld\n", capsnap, follows,
				     flush_tid, capsnap->flush_tid);
				break;
			}
			WARN_ON(capsnap->dirty_pages || capsnap->writing);
2514 2515
			dout(" removing %p cap_snap %p follows %lld\n",
			     inode, capsnap, follows);
S
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2516 2517 2518 2519 2520 2521 2522 2523 2524 2525 2526 2527 2528 2529 2530 2531 2532 2533 2534 2535 2536 2537 2538 2539 2540 2541 2542 2543 2544 2545 2546 2547 2548 2549 2550 2551 2552 2553 2554 2555 2556 2557 2558 2559 2560 2561
			ceph_put_snap_context(capsnap->context);
			list_del(&capsnap->ci_item);
			list_del(&capsnap->flushing_item);
			ceph_put_cap_snap(capsnap);
			drop = 1;
			break;
		} else {
			dout(" skipping cap_snap %p follows %lld\n",
			     capsnap, capsnap->follows);
		}
	}
	spin_unlock(&inode->i_lock);
	if (drop)
		iput(inode);
}

/*
 * Handle TRUNC from MDS, indicating file truncation.
 *
 * caller hold s_mutex.
 */
static void handle_cap_trunc(struct inode *inode,
			     struct ceph_mds_caps *trunc,
			     struct ceph_mds_session *session)
	__releases(inode->i_lock)
{
	struct ceph_inode_info *ci = ceph_inode(inode);
	int mds = session->s_mds;
	int seq = le32_to_cpu(trunc->seq);
	u32 truncate_seq = le32_to_cpu(trunc->truncate_seq);
	u64 truncate_size = le64_to_cpu(trunc->truncate_size);
	u64 size = le64_to_cpu(trunc->size);
	int implemented = 0;
	int dirty = __ceph_caps_dirty(ci);
	int issued = __ceph_caps_issued(ceph_inode(inode), &implemented);
	int queue_trunc = 0;

	issued |= implemented | dirty;

	dout("handle_cap_trunc inode %p mds%d seq %d to %lld seq %d\n",
	     inode, mds, seq, truncate_size, truncate_seq);
	queue_trunc = ceph_fill_file_size(inode, issued,
					  truncate_seq, truncate_size, size);
	spin_unlock(&inode->i_lock);

	if (queue_trunc)
2562
		ceph_queue_vmtruncate(inode);
S
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2563 2564 2565 2566 2567 2568 2569 2570 2571 2572 2573 2574 2575 2576 2577 2578 2579 2580 2581 2582 2583 2584 2585 2586 2587 2588 2589 2590 2591 2592 2593 2594 2595 2596 2597 2598 2599 2600 2601 2602 2603 2604 2605 2606
}

/*
 * Handle EXPORT from MDS.  Cap is being migrated _from_ this mds to a
 * different one.  If we are the most recent migration we've seen (as
 * indicated by mseq), make note of the migrating cap bits for the
 * duration (until we see the corresponding IMPORT).
 *
 * caller holds s_mutex
 */
static void handle_cap_export(struct inode *inode, struct ceph_mds_caps *ex,
			      struct ceph_mds_session *session)
{
	struct ceph_inode_info *ci = ceph_inode(inode);
	int mds = session->s_mds;
	unsigned mseq = le32_to_cpu(ex->migrate_seq);
	struct ceph_cap *cap = NULL, *t;
	struct rb_node *p;
	int remember = 1;

	dout("handle_cap_export inode %p ci %p mds%d mseq %d\n",
	     inode, ci, mds, mseq);

	spin_lock(&inode->i_lock);

	/* make sure we haven't seen a higher mseq */
	for (p = rb_first(&ci->i_caps); p; p = rb_next(p)) {
		t = rb_entry(p, struct ceph_cap, ci_node);
		if (ceph_seq_cmp(t->mseq, mseq) > 0) {
			dout(" higher mseq on cap from mds%d\n",
			     t->session->s_mds);
			remember = 0;
		}
		if (t->session->s_mds == mds)
			cap = t;
	}

	if (cap) {
		if (remember) {
			/* make note */
			ci->i_cap_exporting_mds = mds;
			ci->i_cap_exporting_mseq = mseq;
			ci->i_cap_exporting_issued = cap->issued;
		}
S
Sage Weil 已提交
2607
		__ceph_remove_cap(cap);
S
Sage Weil 已提交
2608
	}
2609
	/* else, we already released it */
S
Sage Weil 已提交
2610 2611 2612 2613 2614 2615 2616 2617 2618 2619 2620 2621 2622 2623 2624 2625 2626 2627 2628 2629 2630 2631 2632 2633 2634 2635 2636 2637 2638 2639 2640 2641 2642 2643 2644 2645 2646 2647 2648 2649 2650 2651 2652 2653 2654 2655 2656 2657 2658 2659 2660 2661 2662 2663 2664 2665 2666 2667 2668 2669 2670 2671 2672

	spin_unlock(&inode->i_lock);
}

/*
 * Handle cap IMPORT.  If there are temp bits from an older EXPORT,
 * clean them up.
 *
 * caller holds s_mutex.
 */
static void handle_cap_import(struct ceph_mds_client *mdsc,
			      struct inode *inode, struct ceph_mds_caps *im,
			      struct ceph_mds_session *session,
			      void *snaptrace, int snaptrace_len)
{
	struct ceph_inode_info *ci = ceph_inode(inode);
	int mds = session->s_mds;
	unsigned issued = le32_to_cpu(im->caps);
	unsigned wanted = le32_to_cpu(im->wanted);
	unsigned seq = le32_to_cpu(im->seq);
	unsigned mseq = le32_to_cpu(im->migrate_seq);
	u64 realmino = le64_to_cpu(im->realm);
	u64 cap_id = le64_to_cpu(im->cap_id);

	if (ci->i_cap_exporting_mds >= 0 &&
	    ceph_seq_cmp(ci->i_cap_exporting_mseq, mseq) < 0) {
		dout("handle_cap_import inode %p ci %p mds%d mseq %d"
		     " - cleared exporting from mds%d\n",
		     inode, ci, mds, mseq,
		     ci->i_cap_exporting_mds);
		ci->i_cap_exporting_issued = 0;
		ci->i_cap_exporting_mseq = 0;
		ci->i_cap_exporting_mds = -1;
	} else {
		dout("handle_cap_import inode %p ci %p mds%d mseq %d\n",
		     inode, ci, mds, mseq);
	}

	down_write(&mdsc->snap_rwsem);
	ceph_update_snap_trace(mdsc, snaptrace, snaptrace+snaptrace_len,
			       false);
	downgrade_write(&mdsc->snap_rwsem);
	ceph_add_cap(inode, session, cap_id, -1,
		     issued, wanted, seq, mseq, realmino, CEPH_CAP_FLAG_AUTH,
		     NULL /* no caps context */);
	try_flush_caps(inode, session, NULL);
	up_read(&mdsc->snap_rwsem);
}

/*
 * Handle a caps message from the MDS.
 *
 * Identify the appropriate session, inode, and call the right handler
 * based on the cap op.
 */
void ceph_handle_caps(struct ceph_mds_session *session,
		      struct ceph_msg *msg)
{
	struct ceph_mds_client *mdsc = session->s_mdsc;
	struct super_block *sb = mdsc->client->sb;
	struct inode *inode;
	struct ceph_cap *cap;
	struct ceph_mds_caps *h;
2673
	int mds = session->s_mds;
S
Sage Weil 已提交
2674
	int op;
2675
	u32 seq, mseq;
S
Sage Weil 已提交
2676 2677 2678
	struct ceph_vino vino;
	u64 cap_id;
	u64 size, max_size;
2679
	u64 tid;
2680
	void *snaptrace;
S
Sage Weil 已提交
2681 2682 2683 2684

	dout("handle_caps from mds%d\n", mds);

	/* decode */
2685
	tid = le64_to_cpu(msg->hdr.tid);
S
Sage Weil 已提交
2686 2687 2688
	if (msg->front.iov_len < sizeof(*h))
		goto bad;
	h = msg->front.iov_base;
2689
	snaptrace = h + 1;
S
Sage Weil 已提交
2690 2691 2692 2693 2694
	op = le32_to_cpu(h->op);
	vino.ino = le64_to_cpu(h->ino);
	vino.snap = CEPH_NOSNAP;
	cap_id = le64_to_cpu(h->cap_id);
	seq = le32_to_cpu(h->seq);
2695
	mseq = le32_to_cpu(h->migrate_seq);
S
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2696 2697 2698 2699 2700 2701 2702 2703 2704 2705 2706 2707 2708 2709
	size = le64_to_cpu(h->size);
	max_size = le64_to_cpu(h->max_size);

	mutex_lock(&session->s_mutex);
	session->s_seq++;
	dout(" mds%d seq %lld cap seq %u\n", session->s_mds, session->s_seq,
	     (unsigned)seq);

	/* lookup ino */
	inode = ceph_find_inode(sb, vino);
	dout(" op %s ino %llx.%llx inode %p\n", ceph_cap_op_name(op), vino.ino,
	     vino.snap, inode);
	if (!inode) {
		dout(" i don't have ino %llx\n", vino.ino);
2710 2711 2712 2713 2714 2715 2716 2717 2718 2719

		if (op == CEPH_CAP_OP_IMPORT)
			__queue_cap_release(session, vino.ino, cap_id,
					    mseq, seq);

		/*
		 * send any full release message to try to move things
		 * along for the mds (who clearly thinks we still have this
		 * cap).
		 */
2720
		ceph_add_cap_releases(mdsc, session, -1);
2721
		ceph_send_cap_releases(mdsc, session);
S
Sage Weil 已提交
2722 2723 2724 2725 2726 2727
		goto done;
	}

	/* these will work even if we don't have a cap yet */
	switch (op) {
	case CEPH_CAP_OP_FLUSHSNAP_ACK:
2728
		handle_cap_flushsnap_ack(inode, tid, h, session);
S
Sage Weil 已提交
2729 2730 2731 2732 2733 2734 2735 2736
		goto done;

	case CEPH_CAP_OP_EXPORT:
		handle_cap_export(inode, h, session);
		goto done;

	case CEPH_CAP_OP_IMPORT:
		handle_cap_import(mdsc, inode, h, session,
2737
				  snaptrace, le32_to_cpu(h->snap_trace_len));
2738 2739 2740
		ceph_check_caps(ceph_inode(inode), CHECK_CAPS_NODELAY,
				session);
		goto done_unlocked;
S
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2741 2742 2743 2744 2745 2746
	}

	/* the rest require a cap */
	spin_lock(&inode->i_lock);
	cap = __get_cap_for_mds(ceph_inode(inode), mds);
	if (!cap) {
2747
		dout(" no cap on %p ino %llx.%llx from mds%d\n",
S
Sage Weil 已提交
2748 2749 2750 2751 2752 2753 2754 2755 2756
		     inode, ceph_ino(inode), ceph_snap(inode), mds);
		spin_unlock(&inode->i_lock);
		goto done;
	}

	/* note that each of these drops i_lock for us */
	switch (op) {
	case CEPH_CAP_OP_REVOKE:
	case CEPH_CAP_OP_GRANT:
2757 2758
		handle_cap_grant(inode, h, session, cap, msg->middle);
		goto done_unlocked;
S
Sage Weil 已提交
2759 2760

	case CEPH_CAP_OP_FLUSH_ACK:
2761
		handle_cap_flush_ack(inode, tid, h, session, cap);
S
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2762 2763 2764 2765 2766 2767 2768 2769 2770 2771 2772 2773 2774
		break;

	case CEPH_CAP_OP_TRUNC:
		handle_cap_trunc(inode, h, session);
		break;

	default:
		spin_unlock(&inode->i_lock);
		pr_err("ceph_handle_caps: unknown cap op %d %s\n", op,
		       ceph_cap_op_name(op));
	}

done:
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	mutex_unlock(&session->s_mutex);
done_unlocked:
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	if (inode)
		iput(inode);
	return;

bad:
	pr_err("ceph_handle_caps: corrupt message\n");
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	ceph_msg_dump(msg);
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	return;
}

/*
 * Delayed work handler to process end of delayed cap release LRU list.
 */
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void ceph_check_delayed_caps(struct ceph_mds_client *mdsc)
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{
	struct ceph_inode_info *ci;
	int flags = CHECK_CAPS_NODELAY;

	dout("check_delayed_caps\n");
	while (1) {
		spin_lock(&mdsc->cap_delay_lock);
		if (list_empty(&mdsc->cap_delay_list))
			break;
		ci = list_first_entry(&mdsc->cap_delay_list,
				      struct ceph_inode_info,
				      i_cap_delay_list);
		if ((ci->i_ceph_flags & CEPH_I_FLUSH) == 0 &&
		    time_before(jiffies, ci->i_hold_caps_max))
			break;
		list_del_init(&ci->i_cap_delay_list);
		spin_unlock(&mdsc->cap_delay_lock);
		dout("check_delayed_caps on %p\n", &ci->vfs_inode);
		ceph_check_caps(ci, flags, NULL);
	}
	spin_unlock(&mdsc->cap_delay_lock);
}

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/*
 * Flush all dirty caps to the mds
 */
void ceph_flush_dirty_caps(struct ceph_mds_client *mdsc)
{
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	struct ceph_inode_info *ci, *nci = NULL;
	struct inode *inode, *ninode = NULL;
	struct list_head *p, *n;
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	dout("flush_dirty_caps\n");
	spin_lock(&mdsc->cap_dirty_lock);
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	list_for_each_safe(p, n, &mdsc->cap_dirty) {
		if (nci) {
			ci = nci;
			inode = ninode;
			ci->i_ceph_flags &= ~CEPH_I_NOFLUSH;
			dout("flush_dirty_caps inode %p (was next inode)\n",
			     inode);
		} else {
			ci = list_entry(p, struct ceph_inode_info,
					i_dirty_item);
			inode = igrab(&ci->vfs_inode);
			BUG_ON(!inode);
			dout("flush_dirty_caps inode %p\n", inode);
		}
		if (n != &mdsc->cap_dirty) {
			nci = list_entry(n, struct ceph_inode_info,
					 i_dirty_item);
			ninode = igrab(&nci->vfs_inode);
			BUG_ON(!ninode);
			nci->i_ceph_flags |= CEPH_I_NOFLUSH;
			dout("flush_dirty_caps next inode %p, noflush\n",
			     ninode);
		} else {
			nci = NULL;
			ninode = NULL;
		}
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		spin_unlock(&mdsc->cap_dirty_lock);
		if (inode) {
			ceph_check_caps(ci, CHECK_CAPS_NODELAY|CHECK_CAPS_FLUSH,
					NULL);
			iput(inode);
		}
		spin_lock(&mdsc->cap_dirty_lock);
	}
	spin_unlock(&mdsc->cap_dirty_lock);
}

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/*
 * Drop open file reference.  If we were the last open file,
 * we may need to release capabilities to the MDS (or schedule
 * their delayed release).
 */
void ceph_put_fmode(struct ceph_inode_info *ci, int fmode)
{
	struct inode *inode = &ci->vfs_inode;
	int last = 0;

	spin_lock(&inode->i_lock);
	dout("put_fmode %p fmode %d %d -> %d\n", inode, fmode,
	     ci->i_nr_by_mode[fmode], ci->i_nr_by_mode[fmode]-1);
	BUG_ON(ci->i_nr_by_mode[fmode] == 0);
	if (--ci->i_nr_by_mode[fmode] == 0)
		last++;
	spin_unlock(&inode->i_lock);

	if (last && ci->i_vino.snap == CEPH_NOSNAP)
		ceph_check_caps(ci, 0, NULL);
}

/*
 * Helpers for embedding cap and dentry lease releases into mds
 * requests.
 *
 * @force is used by dentry_release (below) to force inclusion of a
 * record for the directory inode, even when there aren't any caps to
 * drop.
 */
int ceph_encode_inode_release(void **p, struct inode *inode,
			      int mds, int drop, int unless, int force)
{
	struct ceph_inode_info *ci = ceph_inode(inode);
	struct ceph_cap *cap;
	struct ceph_mds_request_release *rel = *p;
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	int used, dirty;
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	int ret = 0;

	spin_lock(&inode->i_lock);
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	used = __ceph_caps_used(ci);
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	dirty = __ceph_caps_dirty(ci);
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	dout("encode_inode_release %p mds%d used|dirty %s drop %s unless %s\n",
	     inode, mds, ceph_cap_string(used|dirty), ceph_cap_string(drop),
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	     ceph_cap_string(unless));

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	/* only drop unused, clean caps */
	drop &= ~(used | dirty);
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	cap = __get_cap_for_mds(ci, mds);
	if (cap && __cap_is_valid(cap)) {
		if (force ||
		    ((cap->issued & drop) &&
		     (cap->issued & unless) == 0)) {
			if ((cap->issued & drop) &&
			    (cap->issued & unless) == 0) {
				dout("encode_inode_release %p cap %p %s -> "
				     "%s\n", inode, cap,
				     ceph_cap_string(cap->issued),
				     ceph_cap_string(cap->issued & ~drop));
				cap->issued &= ~drop;
				cap->implemented &= ~drop;
				if (ci->i_ceph_flags & CEPH_I_NODELAY) {
					int wanted = __ceph_caps_wanted(ci);
					dout("  wanted %s -> %s (act %s)\n",
					     ceph_cap_string(cap->mds_wanted),
					     ceph_cap_string(cap->mds_wanted &
							     ~wanted),
					     ceph_cap_string(wanted));
					cap->mds_wanted &= wanted;
				}
			} else {
				dout("encode_inode_release %p cap %p %s"
				     " (force)\n", inode, cap,
				     ceph_cap_string(cap->issued));
			}

			rel->ino = cpu_to_le64(ceph_ino(inode));
			rel->cap_id = cpu_to_le64(cap->cap_id);
			rel->seq = cpu_to_le32(cap->seq);
			rel->issue_seq = cpu_to_le32(cap->issue_seq),
			rel->mseq = cpu_to_le32(cap->mseq);
			rel->caps = cpu_to_le32(cap->issued);
			rel->wanted = cpu_to_le32(cap->mds_wanted);
			rel->dname_len = 0;
			rel->dname_seq = 0;
			*p += sizeof(*rel);
			ret = 1;
		} else {
			dout("encode_inode_release %p cap %p %s\n",
			     inode, cap, ceph_cap_string(cap->issued));
		}
	}
	spin_unlock(&inode->i_lock);
	return ret;
}

int ceph_encode_dentry_release(void **p, struct dentry *dentry,
			       int mds, int drop, int unless)
{
	struct inode *dir = dentry->d_parent->d_inode;
	struct ceph_mds_request_release *rel = *p;
	struct ceph_dentry_info *di = ceph_dentry(dentry);
	int force = 0;
	int ret;

	/*
	 * force an record for the directory caps if we have a dentry lease.
	 * this is racy (can't take i_lock and d_lock together), but it
	 * doesn't have to be perfect; the mds will revoke anything we don't
	 * release.
	 */
	spin_lock(&dentry->d_lock);
	if (di->lease_session && di->lease_session->s_mds == mds)
		force = 1;
	spin_unlock(&dentry->d_lock);

	ret = ceph_encode_inode_release(p, dir, mds, drop, unless, force);

	spin_lock(&dentry->d_lock);
	if (ret && di->lease_session && di->lease_session->s_mds == mds) {
		dout("encode_dentry_release %p mds%d seq %d\n",
		     dentry, mds, (int)di->lease_seq);
		rel->dname_len = cpu_to_le32(dentry->d_name.len);
		memcpy(*p, dentry->d_name.name, dentry->d_name.len);
		*p += dentry->d_name.len;
		rel->dname_seq = cpu_to_le32(di->lease_seq);
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		__ceph_mdsc_drop_dentry_lease(dentry);
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	}
	spin_unlock(&dentry->d_lock);
	return ret;
}