caps.c 78.0 KB
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#include "ceph_debug.h"

#include <linux/fs.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/vmalloc.h>
#include <linux/wait.h>

#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 */
	if (!ctx)
		return kmem_cache_alloc(ceph_cap_cachep, GFP_NOFS);

	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;
}

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

	/* prefer mds with WR|WRBUFFER|EXCL caps */
	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.
	 */
	if ((issued & CEPH_CAP_FILE_CACHE) &&
	    (had & CEPH_CAP_FILE_CACHE) == 0)
		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);
	wake_up(&ci->i_cap_wq);
	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);

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	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,
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		     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)
{
	int have = ci->i_snap_caps;
	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) {
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		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;
	for (mode = 0; mode < 4; mode++)
		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;
}

/*
 * caller should hold i_lock, and session s_mutex.
 * returns true if this is the last cap.  if so, caller should iput.
 */
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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;
	struct ceph_mds_client *mdsc = &ceph_client(ci->vfs_inode.i_sb)->mdsc;

	dout("__ceph_remove_cap %p from %p\n", cap, &ci->vfs_inode);

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

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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;
	}
	spin_unlock(&session->s_cap_lock);

	if (cap->session == NULL)
		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);

	msg = ceph_msg_new(CEPH_MSG_CLIENT_CAPS, sizeof(*fc), 0, 0, NULL);
	if (IS_ERR(msg))
		return PTR_ERR(msg);

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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;
}

/*
 * Queue cap releases when an inode is dropped from our
 * cache.
 */
void ceph_queue_caps_release(struct inode *inode)
{
	struct ceph_inode_info *ci = ceph_inode(inode);
	struct rb_node *p;

	spin_lock(&inode->i_lock);
	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;
		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 %p release to mds%d msg %p (%d left)\n",
		     inode, 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(ceph_ino(inode));
		item->cap_id = cpu_to_le64(cap->cap_id);
		item->migrate_seq = cpu_to_le32(cap->mseq);
		item->seq = cpu_to_le32(cap->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,
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				       &session->s_cap_releases_done);
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		} 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);
		p = rb_next(p);
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		__ceph_remove_cap(cap);
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	}
	spin_unlock(&inode->i_lock);
}

/*
 * 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;
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	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;

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	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)
		wake_up(&ci->i_cap_wq);

	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;

		/* 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);
}

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1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319
/*
 * 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)
{
	struct ceph_mds_client *mdsc = &ceph_client(ci->vfs_inode.i_sb)->mdsc;
	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);
}

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/*
 * Add dirty inode to the flushing list.  Assigned a seq number so we
 * can wait for caps to flush without starving.
1323 1324
 *
 * Called under i_lock.
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 */
1326
static int __mark_caps_flushing(struct inode *inode,
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				 struct ceph_mds_session *session)
{
	struct ceph_mds_client *mdsc = &ceph_client(inode->i_sb)->mdsc;
	struct ceph_inode_info *ci = ceph_inode(inode);
1331
	int flushing;
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1333
	BUG_ON(ci->i_dirty_caps == 0);
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	BUG_ON(list_empty(&ci->i_dirty_item));
1335 1336 1337 1338 1339 1340 1341 1342

	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;
1343
	dout(" inode %p now !dirty\n", inode);
1344

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	spin_lock(&mdsc->cap_dirty_lock);
1346 1347 1348
	list_del_init(&ci->i_dirty_item);

	ci->i_cap_flush_seq = ++mdsc->cap_flush_seq;
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	if (list_empty(&ci->i_flushing_item)) {
		list_add_tail(&ci->i_flushing_item, &session->s_cap_flushing);
		mdsc->num_cap_flushing++;
1352 1353 1354 1355 1356
		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,
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		     ci->i_cap_flush_seq);
	}
	spin_unlock(&mdsc->cap_dirty_lock);
1360 1361

	return flushing;
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}

1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383 1384 1385 1386 1387 1388 1389 1390 1391 1392 1393 1394 1395 1396 1397 1398
/*
 * 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;
}

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1399 1400 1401 1402 1403 1404 1405 1406 1407 1408 1409 1410 1411 1412 1413 1414 1415 1416 1417 1418 1419
/*
 * 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)
{
	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 */
	int drop_session_lock = session ? 0 : 1;
S
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	int issued, implemented, want, retain, revoking, flushing = 0;
S
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1421 1422 1423 1424 1425
	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
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	int queue_invalidate = 0;
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1427 1428 1429 1430 1431 1432 1433 1434 1435 1436 1437 1438 1439 1440 1441 1442 1443 1444 1445 1446 1447
	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;
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	issued = __ceph_caps_issued(ci, &implemented);
	revoking = implemented & ~issued;
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1450 1451 1452 1453 1454 1455 1456 1457 1458 1459 1460 1461 1462 1463 1464 1465 1466 1467

	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"
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	     " issued %s revoking %s retain %s %s%s%s\n", inode,
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1469 1470 1471
	     ceph_cap_string(file_wanted),
	     ceph_cap_string(used), ceph_cap_string(ci->i_dirty_caps),
	     ceph_cap_string(ci->i_flushing_caps),
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1472
	     ceph_cap_string(issued), ceph_cap_string(revoking),
S
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1473 1474 1475 1476 1477 1478 1479 1480 1481 1482 1483 1484 1485
	     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
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1486 1487
	    (file_wanted == 0 ||                     /* no open files */
	     (revoking & CEPH_CAP_FILE_CACHE)) &&     /*  or revoking cache */
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	    !tried_invalidate) {
		dout("check_caps trying to invalidate on %p\n", inode);
1490 1491 1492 1493 1494 1495 1496 1497 1498 1499 1500 1501
		if (try_nonblocking_invalidate(inode) < 0) {
			if (revoking & CEPH_CAP_FILE_CACHE) {
				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);
			}
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1502 1503 1504 1505 1506 1507 1508 1509 1510 1511 1512 1513 1514 1515 1516 1517 1518 1519 1520
		}
		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
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1521
			dout(" mds%d revoking %s\n", cap->mds,
S
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1522 1523 1524 1525 1526 1527 1528 1529 1530 1531 1532 1533 1534 1535 1536 1537 1538 1539 1540 1541 1542 1543 1544 1545 1546 1547 1548 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 1606 1607 1608 1609 1610
			     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:
		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;
		}

1611 1612
		if (cap == ci->i_auth_cap && ci->i_dirty_caps)
			flushing = __mark_caps_flushing(inode, session);
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1613 1614 1615 1616 1617 1618 1619 1620 1621 1622 1623 1624 1625 1626 1627 1628 1629 1630 1631 1632 1633 1634 1635

		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
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1636
	if (queue_invalidate)
1637
		ceph_queue_invalidate(inode);
S
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1638

S
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1639 1640 1641 1642 1643 1644 1645 1646 1647 1648 1649 1650 1651 1652 1653 1654 1655 1656 1657 1658 1659 1660 1661 1662 1663 1664 1665 1666 1667 1668 1669 1670 1671 1672 1673
	if (session && drop_session_lock)
		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)
{
	struct ceph_mds_client *mdsc = &ceph_client(inode->i_sb)->mdsc;
	struct ceph_inode_info *ci = ceph_inode(inode);
	int unlock_session = session ? 0 : 1;
	int flushing = 0;

retry:
	spin_lock(&inode->i_lock);
	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;

1674
		flushing = __mark_caps_flushing(inode, session);
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Sage Weil 已提交
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		/* __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);
	int dirty, i, ret = 1;

	spin_lock(&inode->i_lock);
	dirty = __ceph_caps_dirty(ci);
	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);
}

int ceph_fsync(struct file *file, struct dentry *dentry, int datasync)
{
	struct inode *inode = dentry->d_inode;
	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.
 */
int ceph_write_inode(struct inode *inode, int wait)
{
	struct ceph_inode_info *ci = ceph_inode(inode);
	unsigned flush_tid;
	int err = 0;
	int dirty;

	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 {
		struct ceph_mds_client *mdsc = &ceph_client(inode->i_sb)->mdsc;

		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);
			spin_unlock(&inode->i_lock);
		}
	}
}

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;

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

	/* make sure we _have_ some caps! */
	if (!__ceph_is_any_caps(ci)) {
		dout("get_cap_refs %p no real caps\n", inode);
		*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);

	dout("put_cap_refs %p had %s %s\n", inode, ceph_cap_string(had),
	     last ? "last" : "");

	if (last && !flushsnaps)
		ceph_check_caps(ci, 0, NULL);
	else if (flushsnaps)
		ceph_flush_snaps(ci);
	if (wake)
		wake_up(&ci->i_cap_wq);
	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;
	int last_snap = 0;
	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;
				capsnap->dirty_pages -= nr;
				last_snap = !capsnap->dirty_pages;
				break;
			}
		}
		BUG_ON(!found);
		dout("put_wrbuffer_cap_refs on %p cap_snap %p "
		     " snap %lld %d/%d -> %d/%d %s%s\n",
		     inode, capsnap, capsnap->context->seq,
		     ci->i_wrbuffer_ref+nr, capsnap->dirty_pages + nr,
		     ci->i_wrbuffer_ref, capsnap->dirty_pages,
		     last ? " (wrbuffer last)" : "",
		     last_snap ? " (capsnap last)" : "");
	}

	spin_unlock(&inode->i_lock);

	if (last) {
		ceph_check_caps(ci, CHECK_CAPS_AUTHONLY, NULL);
		iput(inode);
	} else if (last_snap) {
		ceph_flush_snaps(ci);
		wake_up(&ci->i_cap_wq);
	}
}

/*
 * Handle a cap GRANT message from the MDS.  (Note that a GRANT may
 * actually be a revocation if it specifies a smaller cap set.)
 *
 * caller holds s_mutex.
 * return value:
 *  0 - ok
 *  1 - check_caps on auth cap only (writeback)
 *  2 - check_caps (ack revoke)
 */
static int 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)
	__releases(inode->i_lock)

{
	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;
	int reply = 0;
	int wake = 0;
	int writeback = 0;
	int revoked_rdcache = 0;
2212
	int queue_invalidate = 0;
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	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.)
	 */
	if (((cap->issued & ~newcaps) & CEPH_CAP_FILE_CACHE) &&
2225
	    !ci->i_wrbuffer_ref) {
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		if (try_nonblocking_invalidate(inode) == 0) {
			revoked_rdcache = 1;
		} else {
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			/* there were locked pages.. invalidate later
			   in a separate thread. */
			if (ci->i_rdcache_revoking != ci->i_rdcache_gen) {
2232
				queue_invalidate = 1;
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				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);

2243
	cap->cap_gen = session->s_cap_gen;
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	__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)
			reply = 1;     /* initiate writeback in check_caps */
		else if (((used & ~newcaps) & CEPH_CAP_FILE_CACHE) == 0 ||
			   revoked_rdcache)
			reply = 2;     /* send revoke ack in check_caps */
		cap->issued = newcaps;
	} 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;
	}

	spin_unlock(&inode->i_lock);
2340
	if (writeback)
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		/*
		 * queue inode for writeback: we can't actually call
		 * filemap_write_and_wait, etc. from message handler
		 * context.
		 */
2346 2347 2348
		ceph_queue_writeback(inode);
	if (queue_invalidate)
		ceph_queue_invalidate(inode);
S
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	if (wake)
		wake_up(&ci->i_cap_wq);
	return reply;
}

/*
 * Handle FLUSH_ACK from MDS, indicating that metadata we sent to the
 * MDS has been safely committed.
 */
2358
static void handle_cap_flush_ack(struct inode *inode, u64 flush_tid,
S
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2359 2360 2361 2362 2363 2364 2365 2366 2367 2368
				 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);
	struct ceph_mds_client *mdsc = &ceph_client(inode->i_sb)->mdsc;
	unsigned seq = le32_to_cpu(m->seq);
	int dirty = le32_to_cpu(m->dirty);
	int cleaned = 0;
2369
	int drop = 0;
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2370 2371 2372 2373 2374 2375 2376 2377 2378 2379 2380 2381 2382 2383 2384 2385 2386 2387 2388 2389 2390 2391 2392 2393 2394 2395 2396 2397 2398 2399
	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--;
		wake_up(&mdsc->cap_flushing_wq);
		dout(" inode %p now !flushing\n", inode);
2400 2401 2402 2403 2404

		if (ci->i_dirty_caps == 0) {
			dout(" inode %p now clean\n", inode);
			BUG_ON(!list_empty(&ci->i_dirty_item));
			drop = 1;
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2405 2406
		} else {
			BUG_ON(list_empty(&ci->i_dirty_item));
2407
		}
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2408 2409 2410 2411 2412 2413
	}
	spin_unlock(&mdsc->cap_dirty_lock);
	wake_up(&ci->i_cap_wq);

out:
	spin_unlock(&inode->i_lock);
2414
	if (drop)
S
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2415 2416 2417 2418 2419 2420 2421 2422 2423
		iput(inode);
}

/*
 * Handle FLUSHSNAP_ACK.  MDS has flushed snap data to disk and we can
 * throw away our cap_snap.
 *
 * Caller hold s_mutex.
 */
2424
static void handle_cap_flushsnap_ack(struct inode *inode, u64 flush_tid,
S
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2425 2426 2427 2428 2429 2430 2431 2432 2433 2434 2435 2436 2437 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 2466 2467 2468 2469 2470 2471 2472 2473 2474 2475 2476 2477 2478 2479 2480 2481 2482 2483 2484 2485 2486 2487 2488 2489 2490 2491 2492 2493
				     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);
			dout(" removing cap_snap %p follows %lld\n",
			     capsnap, follows);
			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)
2494
		ceph_queue_vmtruncate(inode);
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}

/*
 * 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
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2539
		__ceph_remove_cap(cap);
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2540 2541 2542 2543 2544 2545 2546 2547 2548 2549 2550 2551 2552 2553 2554 2555 2556 2557 2558 2559 2560 2561 2562 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 2607 2608 2609 2610 2611
	} else {
		WARN_ON(!cap);
	}

	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;
	int mds = le64_to_cpu(msg->hdr.src.name.num);
	int op;
	u32 seq;
	struct ceph_vino vino;
	u64 cap_id;
	u64 size, max_size;
2612
	u64 tid;
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2613 2614 2615 2616 2617 2618
	int check_caps = 0;
	int r;

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

	/* decode */
2619
	tid = le64_to_cpu(msg->hdr.tid);
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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
	if (msg->front.iov_len < sizeof(*h))
		goto bad;
	h = msg->front.iov_base;
	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);
	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);
		goto done;
	}

	/* these will work even if we don't have a cap yet */
	switch (op) {
	case CEPH_CAP_OP_FLUSHSNAP_ACK:
2648
		handle_cap_flushsnap_ack(inode, tid, h, session);
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		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,
				  msg->middle,
				  le32_to_cpu(h->snap_trace_len));
		check_caps = 1; /* we may have sent a RELEASE to the old auth */
		goto done;
	}

	/* the rest require a cap */
	spin_lock(&inode->i_lock);
	cap = __get_cap_for_mds(ceph_inode(inode), mds);
	if (!cap) {
		dout("no cap on %p ino %llx.%llx from mds%d, releasing\n",
		     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:
		r = handle_cap_grant(inode, h, session, cap, msg->middle);
		if (r == 1)
			ceph_check_caps(ceph_inode(inode),
					CHECK_CAPS_NODELAY|CHECK_CAPS_AUTHONLY,
					session);
		else if (r == 2)
			ceph_check_caps(ceph_inode(inode),
					CHECK_CAPS_NODELAY,
					session);
		break;

	case CEPH_CAP_OP_FLUSH_ACK:
2689
		handle_cap_flush_ack(inode, tid, h, session, cap);
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		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:
	mutex_unlock(&session->s_mutex);

	if (check_caps)
		ceph_check_caps(ceph_inode(inode), CHECK_CAPS_NODELAY, NULL);
	if (inode)
		iput(inode);
	return;

bad:
	pr_err("ceph_handle_caps: corrupt message\n");
2713
	ceph_msg_dump(msg);
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2714 2715 2716 2717 2718 2719
	return;
}

/*
 * Delayed work handler to process end of delayed cap release LRU list.
 */
2720
void ceph_check_delayed_caps(struct ceph_mds_client *mdsc)
S
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2721 2722 2723 2724 2725 2726 2727 2728 2729 2730 2731 2732 2733 2734 2735 2736 2737 2738 2739 2740 2741 2742 2743
{
	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);
}

2744 2745 2746 2747 2748 2749 2750 2751 2752 2753 2754 2755 2756 2757 2758 2759 2760 2761 2762 2763 2764 2765 2766 2767 2768 2769
/*
 * Flush all dirty caps to the mds
 */
void ceph_flush_dirty_caps(struct ceph_mds_client *mdsc)
{
	struct ceph_inode_info *ci;
	struct inode *inode;

	dout("flush_dirty_caps\n");
	spin_lock(&mdsc->cap_dirty_lock);
	while (!list_empty(&mdsc->cap_dirty)) {
		ci = list_first_entry(&mdsc->cap_dirty,
				      struct ceph_inode_info,
				      i_dirty_item);
		inode = igrab(&ci->vfs_inode);
		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);
}

S
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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;
	int ret = 0;

	dout("encode_inode_release %p mds%d drop %s unless %s\n", inode,
	     mds, ceph_cap_string(drop), ceph_cap_string(unless));

	spin_lock(&inode->i_lock);
	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);
	}
	spin_unlock(&dentry->d_lock);
	return ret;
}