file.c 22.6 KB
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#include <linux/ceph/ceph_debug.h>
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#include <linux/module.h>
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#include <linux/sched.h>
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#include <linux/slab.h>
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#include <linux/file.h>
#include <linux/namei.h>
#include <linux/writeback.h>

#include "super.h"
#include "mds_client.h"

/*
 * Ceph file operations
 *
 * Implement basic open/close functionality, and implement
 * read/write.
 *
 * We implement three modes of file I/O:
 *  - buffered uses the generic_file_aio_{read,write} helpers
 *
 *  - synchronous is used when there is multi-client read/write
 *    sharing, avoids the page cache, and synchronously waits for an
 *    ack from the OSD.
 *
 *  - direct io takes the variant of the sync path that references
 *    user pages directly.
 *
 * fsync() flushes and waits on dirty pages, but just queues metadata
 * for writeback: since the MDS can recover size and mtime there is no
 * need to wait for MDS acknowledgement.
 */


/*
 * Prepare an open request.  Preallocate ceph_cap to avoid an
 * inopportune ENOMEM later.
 */
static struct ceph_mds_request *
prepare_open_request(struct super_block *sb, int flags, int create_mode)
{
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	struct ceph_fs_client *fsc = ceph_sb_to_client(sb);
	struct ceph_mds_client *mdsc = fsc->mdsc;
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	struct ceph_mds_request *req;
	int want_auth = USE_ANY_MDS;
	int op = (flags & O_CREAT) ? CEPH_MDS_OP_CREATE : CEPH_MDS_OP_OPEN;

	if (flags & (O_WRONLY|O_RDWR|O_CREAT|O_TRUNC))
		want_auth = USE_AUTH_MDS;

	req = ceph_mdsc_create_request(mdsc, op, want_auth);
	if (IS_ERR(req))
		goto out;
	req->r_fmode = ceph_flags_to_mode(flags);
	req->r_args.open.flags = cpu_to_le32(flags);
	req->r_args.open.mode = cpu_to_le32(create_mode);
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	req->r_args.open.preferred = cpu_to_le32(-1);
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out:
	return req;
}

/*
 * initialize private struct file data.
 * if we fail, clean up by dropping fmode reference on the ceph_inode
 */
static int ceph_init_file(struct inode *inode, struct file *file, int fmode)
{
	struct ceph_file_info *cf;
	int ret = 0;

	switch (inode->i_mode & S_IFMT) {
	case S_IFREG:
	case S_IFDIR:
		dout("init_file %p %p 0%o (regular)\n", inode, file,
		     inode->i_mode);
		cf = kmem_cache_alloc(ceph_file_cachep, GFP_NOFS | __GFP_ZERO);
		if (cf == NULL) {
			ceph_put_fmode(ceph_inode(inode), fmode); /* clean up */
			return -ENOMEM;
		}
		cf->fmode = fmode;
		cf->next_offset = 2;
		file->private_data = cf;
		BUG_ON(inode->i_fop->release != ceph_release);
		break;

	case S_IFLNK:
		dout("init_file %p %p 0%o (symlink)\n", inode, file,
		     inode->i_mode);
		ceph_put_fmode(ceph_inode(inode), fmode); /* clean up */
		break;

	default:
		dout("init_file %p %p 0%o (special)\n", inode, file,
		     inode->i_mode);
		/*
		 * we need to drop the open ref now, since we don't
		 * have .release set to ceph_release.
		 */
		ceph_put_fmode(ceph_inode(inode), fmode); /* clean up */
		BUG_ON(inode->i_fop->release == ceph_release);

		/* call the proper open fop */
		ret = inode->i_fop->open(inode, file);
	}
	return ret;
}

/*
 * If the filp already has private_data, that means the file was
 * already opened by intent during lookup, and we do nothing.
 *
 * If we already have the requisite capabilities, we can satisfy
 * the open request locally (no need to request new caps from the
 * MDS).  We do, however, need to inform the MDS (asynchronously)
 * if our wanted caps set expands.
 */
int ceph_open(struct inode *inode, struct file *file)
{
	struct ceph_inode_info *ci = ceph_inode(inode);
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	struct ceph_fs_client *fsc = ceph_sb_to_client(inode->i_sb);
	struct ceph_mds_client *mdsc = fsc->mdsc;
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	struct ceph_mds_request *req;
	struct ceph_file_info *cf = file->private_data;
	struct inode *parent_inode = file->f_dentry->d_parent->d_inode;
	int err;
	int flags, fmode, wanted;

	if (cf) {
		dout("open file %p is already opened\n", file);
		return 0;
	}

	/* filter out O_CREAT|O_EXCL; vfs did that already.  yuck. */
	flags = file->f_flags & ~(O_CREAT|O_EXCL);
	if (S_ISDIR(inode->i_mode))
		flags = O_DIRECTORY;  /* mds likes to know */

	dout("open inode %p ino %llx.%llx file %p flags %d (%d)\n", inode,
	     ceph_vinop(inode), file, flags, file->f_flags);
	fmode = ceph_flags_to_mode(flags);
	wanted = ceph_caps_for_mode(fmode);

	/* snapped files are read-only */
	if (ceph_snap(inode) != CEPH_NOSNAP && (file->f_mode & FMODE_WRITE))
		return -EROFS;

	/* trivially open snapdir */
	if (ceph_snap(inode) == CEPH_SNAPDIR) {
		spin_lock(&inode->i_lock);
		__ceph_get_fmode(ci, fmode);
		spin_unlock(&inode->i_lock);
		return ceph_init_file(inode, file, fmode);
	}

	/*
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	 * No need to block if we have caps on the auth MDS (for
	 * write) or any MDS (for read).  Update wanted set
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	 * asynchronously.
	 */
	spin_lock(&inode->i_lock);
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	if (__ceph_is_any_real_caps(ci) &&
	    (((fmode & CEPH_FILE_MODE_WR) == 0) || ci->i_auth_cap)) {
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		int mds_wanted = __ceph_caps_mds_wanted(ci);
		int issued = __ceph_caps_issued(ci, NULL);

		dout("open %p fmode %d want %s issued %s using existing\n",
		     inode, fmode, ceph_cap_string(wanted),
		     ceph_cap_string(issued));
		__ceph_get_fmode(ci, fmode);
		spin_unlock(&inode->i_lock);

		/* adjust wanted? */
		if ((issued & wanted) != wanted &&
		    (mds_wanted & wanted) != wanted &&
		    ceph_snap(inode) != CEPH_SNAPDIR)
			ceph_check_caps(ci, 0, NULL);

		return ceph_init_file(inode, file, fmode);
	} else if (ceph_snap(inode) != CEPH_NOSNAP &&
		   (ci->i_snap_caps & wanted) == wanted) {
		__ceph_get_fmode(ci, fmode);
		spin_unlock(&inode->i_lock);
		return ceph_init_file(inode, file, fmode);
	}
	spin_unlock(&inode->i_lock);

	dout("open fmode %d wants %s\n", fmode, ceph_cap_string(wanted));
	req = prepare_open_request(inode->i_sb, flags, 0);
	if (IS_ERR(req)) {
		err = PTR_ERR(req);
		goto out;
	}
	req->r_inode = igrab(inode);
	req->r_num_caps = 1;
	err = ceph_mdsc_do_request(mdsc, parent_inode, req);
	if (!err)
		err = ceph_init_file(inode, file, req->r_fmode);
	ceph_mdsc_put_request(req);
	dout("open result=%d on %llx.%llx\n", err, ceph_vinop(inode));
out:
	return err;
}


/*
 * Do a lookup + open with a single request.
 *
 * If this succeeds, but some subsequent check in the vfs
 * may_open() fails, the struct *file gets cleaned up (i.e.
 * ceph_release gets called).  So fear not!
 */
/*
 * flags
 *  path_lookup_open   -> LOOKUP_OPEN
 *  path_lookup_create -> LOOKUP_OPEN|LOOKUP_CREATE
 */
struct dentry *ceph_lookup_open(struct inode *dir, struct dentry *dentry,
				struct nameidata *nd, int mode,
				int locked_dir)
{
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	struct ceph_fs_client *fsc = ceph_sb_to_client(dir->i_sb);
	struct ceph_mds_client *mdsc = fsc->mdsc;
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	struct file *file = nd->intent.open.file;
	struct inode *parent_inode = get_dentry_parent_inode(file->f_dentry);
	struct ceph_mds_request *req;
	int err;
	int flags = nd->intent.open.flags - 1;  /* silly vfs! */

	dout("ceph_lookup_open dentry %p '%.*s' flags %d mode 0%o\n",
	     dentry, dentry->d_name.len, dentry->d_name.name, flags, mode);

	/* do the open */
	req = prepare_open_request(dir->i_sb, flags, mode);
	if (IS_ERR(req))
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		return ERR_CAST(req);
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	req->r_dentry = dget(dentry);
	req->r_num_caps = 2;
	if (flags & O_CREAT) {
		req->r_dentry_drop = CEPH_CAP_FILE_SHARED;
		req->r_dentry_unless = CEPH_CAP_FILE_EXCL;
	}
	req->r_locked_dir = dir;           /* caller holds dir->i_mutex */
	err = ceph_mdsc_do_request(mdsc, parent_inode, req);
	dentry = ceph_finish_lookup(req, dentry, err);
	if (!err && (flags & O_CREAT) && !req->r_reply_info.head->is_dentry)
		err = ceph_handle_notrace_create(dir, dentry);
	if (!err)
		err = ceph_init_file(req->r_dentry->d_inode, file,
				     req->r_fmode);
	ceph_mdsc_put_request(req);
	dout("ceph_lookup_open result=%p\n", dentry);
	return dentry;
}

int ceph_release(struct inode *inode, struct file *file)
{
	struct ceph_inode_info *ci = ceph_inode(inode);
	struct ceph_file_info *cf = file->private_data;

	dout("release inode %p file %p\n", inode, file);
	ceph_put_fmode(ci, cf->fmode);
	if (cf->last_readdir)
		ceph_mdsc_put_request(cf->last_readdir);
	kfree(cf->last_name);
	kfree(cf->dir_info);
	dput(cf->dentry);
	kmem_cache_free(ceph_file_cachep, cf);
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	/* wake up anyone waiting for caps on this inode */
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	wake_up_all(&ci->i_cap_wq);
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	return 0;
}

/*
 * Read a range of bytes striped over one or more objects.  Iterate over
 * objects we stripe over.  (That's not atomic, but good enough for now.)
 *
 * If we get a short result from the OSD, check against i_size; we need to
 * only return a short read to the caller if we hit EOF.
 */
static int striped_read(struct inode *inode,
			u64 off, u64 len,
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			struct page **pages, int num_pages,
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			int *checkeof, bool align_to_pages,
			unsigned long buf_align)
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{
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	struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
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	struct ceph_inode_info *ci = ceph_inode(inode);
	u64 pos, this_len;
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	int io_align, page_align;
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	int page_off = off & ~PAGE_CACHE_MASK; /* first byte's offset in page */
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	int left, pages_left;
	int read;
	struct page **page_pos;
	int ret;
	bool hit_stripe, was_short;

	/*
	 * we may need to do multiple reads.  not atomic, unfortunately.
	 */
	pos = off;
	left = len;
	page_pos = pages;
	pages_left = num_pages;
	read = 0;
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	io_align = off & ~PAGE_MASK;
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	if (align_to_pages)
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		page_align = (pos - io_align + buf_align) & ~PAGE_MASK;
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	else
		page_align = pos & ~PAGE_MASK;
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	this_len = left;
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	ret = ceph_osdc_readpages(&fsc->client->osdc, ceph_vino(inode),
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				  &ci->i_layout, pos, &this_len,
				  ci->i_truncate_seq,
				  ci->i_truncate_size,
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				  page_pos, pages_left, page_align);
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	hit_stripe = this_len < left;
	was_short = ret >= 0 && ret < this_len;
	if (ret == -ENOENT)
		ret = 0;
	dout("striped_read %llu~%u (read %u) got %d%s%s\n", pos, left, read,
	     ret, hit_stripe ? " HITSTRIPE" : "", was_short ? " SHORT" : "");

	if (ret > 0) {
		int didpages =
			((pos & ~PAGE_CACHE_MASK) + ret) >> PAGE_CACHE_SHIFT;

		if (read < pos - off) {
			dout(" zero gap %llu to %llu\n", off + read, pos);
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			ceph_zero_page_vector_range(page_off + read,
						    pos - off - read, pages);
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		}
		pos += ret;
		read = pos - off;
		left -= ret;
		page_pos += didpages;
		pages_left -= didpages;

		/* hit stripe? */
		if (left && hit_stripe)
			goto more;
	}

	if (was_short) {
		/* was original extent fully inside i_size? */
		if (pos + left <= inode->i_size) {
			dout("zero tail\n");
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			ceph_zero_page_vector_range(page_off + read, len - read,
						    pages);
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			read = len;
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			goto out;
		}

		/* check i_size */
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		*checkeof = 1;
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	}

out:
	if (ret >= 0)
		ret = read;
	dout("striped_read returns %d\n", ret);
	return ret;
}

/*
 * Completely synchronous read and write methods.  Direct from __user
 * buffer to osd, or directly to user pages (if O_DIRECT).
 *
 * If the read spans object boundary, just do multiple reads.
 */
static ssize_t ceph_sync_read(struct file *file, char __user *data,
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			      unsigned len, loff_t *poff, int *checkeof)
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{
	struct inode *inode = file->f_dentry->d_inode;
	struct page **pages;
	u64 off = *poff;
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	int num_pages, ret;
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	dout("sync_read on file %p %llu~%u %s\n", file, off, len,
	     (file->f_flags & O_DIRECT) ? "O_DIRECT" : "");

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	if (file->f_flags & O_DIRECT) {
		num_pages = calc_pages_for((unsigned long)data, len);
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		pages = ceph_get_direct_page_vector(data, num_pages, true);
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	} else {
		num_pages = calc_pages_for(off, len);
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		pages = ceph_alloc_page_vector(num_pages, GFP_NOFS);
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	}
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	if (IS_ERR(pages))
		return PTR_ERR(pages);

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	/*
	 * flush any page cache pages in this range.  this
	 * will make concurrent normal and sync io slow,
	 * but it will at least behave sensibly when they are
	 * in sequence.
	 */
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	ret = filemap_write_and_wait(inode->i_mapping);
	if (ret < 0)
		goto done;

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	ret = striped_read(inode, off, len, pages, num_pages, checkeof,
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			   file->f_flags & O_DIRECT,
			   (unsigned long)data & ~PAGE_MASK);
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	if (ret >= 0 && (file->f_flags & O_DIRECT) == 0)
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		ret = ceph_copy_page_vector_to_user(pages, data, off, ret);
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	if (ret >= 0)
		*poff = off + ret;

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done:
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	if (file->f_flags & O_DIRECT)
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		ceph_put_page_vector(pages, num_pages, true);
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	else
		ceph_release_page_vector(pages, num_pages);
	dout("sync_read result %d\n", ret);
	return ret;
}

/*
 * Write commit callback, called if we requested both an ACK and
 * ONDISK commit reply from the OSD.
 */
static void sync_write_commit(struct ceph_osd_request *req,
			      struct ceph_msg *msg)
{
	struct ceph_inode_info *ci = ceph_inode(req->r_inode);

	dout("sync_write_commit %p tid %llu\n", req, req->r_tid);
	spin_lock(&ci->i_unsafe_lock);
	list_del_init(&req->r_unsafe_item);
	spin_unlock(&ci->i_unsafe_lock);
	ceph_put_cap_refs(ci, CEPH_CAP_FILE_WR);
}

/*
 * Synchronous write, straight from __user pointer or user pages (if
 * O_DIRECT).
 *
 * If write spans object boundary, just do multiple writes.  (For a
 * correct atomic write, we should e.g. take write locks on all
 * objects, rollback on failure, etc.)
 */
static ssize_t ceph_sync_write(struct file *file, const char __user *data,
			       size_t left, loff_t *offset)
{
	struct inode *inode = file->f_dentry->d_inode;
	struct ceph_inode_info *ci = ceph_inode(inode);
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	struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
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	struct ceph_osd_request *req;
	struct page **pages;
	int num_pages;
	long long unsigned pos;
	u64 len;
	int written = 0;
	int flags;
	int do_sync = 0;
	int check_caps = 0;
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	int page_align, io_align;
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	unsigned long buf_align;
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	int ret;
	struct timespec mtime = CURRENT_TIME;

	if (ceph_snap(file->f_dentry->d_inode) != CEPH_NOSNAP)
		return -EROFS;

	dout("sync_write on file %p %lld~%u %s\n", file, *offset,
	     (unsigned)left, (file->f_flags & O_DIRECT) ? "O_DIRECT" : "");

	if (file->f_flags & O_APPEND)
		pos = i_size_read(inode);
	else
		pos = *offset;

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	io_align = pos & ~PAGE_MASK;
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	buf_align = (unsigned long)data & ~PAGE_MASK;
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	ret = filemap_write_and_wait_range(inode->i_mapping, pos, pos + left);
	if (ret < 0)
		return ret;

	ret = invalidate_inode_pages2_range(inode->i_mapping,
					    pos >> PAGE_CACHE_SHIFT,
					    (pos + left) >> PAGE_CACHE_SHIFT);
	if (ret < 0)
		dout("invalidate_inode_pages2_range returned %d\n", ret);

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	flags = CEPH_OSD_FLAG_ORDERSNAP |
		CEPH_OSD_FLAG_ONDISK |
		CEPH_OSD_FLAG_WRITE;
	if ((file->f_flags & (O_SYNC|O_DIRECT)) == 0)
		flags |= CEPH_OSD_FLAG_ACK;
	else
		do_sync = 1;

	/*
	 * we may need to do multiple writes here if we span an object
	 * boundary.  this isn't atomic, unfortunately.  :(
	 */
more:
	len = left;
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	if (file->f_flags & O_DIRECT) {
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		/* write from beginning of first page, regardless of
		   io alignment */
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		page_align = (pos - io_align + buf_align) & ~PAGE_MASK;
		num_pages = calc_pages_for((unsigned long)data, len);
	} else {
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		page_align = pos & ~PAGE_MASK;
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		num_pages = calc_pages_for(pos, len);
	}
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	req = ceph_osdc_new_request(&fsc->client->osdc, &ci->i_layout,
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				    ceph_vino(inode), pos, &len,
				    CEPH_OSD_OP_WRITE, flags,
				    ci->i_snap_realm->cached_context,
				    do_sync,
				    ci->i_truncate_seq, ci->i_truncate_size,
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				    &mtime, false, 2, page_align);
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	if (!req)
		return -ENOMEM;
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	if (file->f_flags & O_DIRECT) {
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		pages = ceph_get_direct_page_vector(data, num_pages, false);
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		if (IS_ERR(pages)) {
			ret = PTR_ERR(pages);
			goto out;
		}

		/*
		 * throw out any page cache pages in this range. this
		 * may block.
		 */
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		truncate_inode_pages_range(inode->i_mapping, pos,
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					   (pos+len) | (PAGE_CACHE_SIZE-1));
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	} else {
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		pages = ceph_alloc_page_vector(num_pages, GFP_NOFS);
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		if (IS_ERR(pages)) {
			ret = PTR_ERR(pages);
			goto out;
		}
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		ret = ceph_copy_user_to_page_vector(pages, data, pos, len);
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		if (ret < 0) {
			ceph_release_page_vector(pages, num_pages);
			goto out;
		}

		if ((file->f_flags & O_SYNC) == 0) {
			/* get a second commit callback */
			req->r_safe_callback = sync_write_commit;
			req->r_own_pages = 1;
		}
	}
	req->r_pages = pages;
	req->r_num_pages = num_pages;
	req->r_inode = inode;

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	ret = ceph_osdc_start_request(&fsc->client->osdc, req, false);
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	if (!ret) {
		if (req->r_safe_callback) {
			/*
			 * Add to inode unsafe list only after we
			 * start_request so that a tid has been assigned.
			 */
			spin_lock(&ci->i_unsafe_lock);
567 568
			list_add_tail(&req->r_unsafe_item,
				      &ci->i_unsafe_writes);
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			spin_unlock(&ci->i_unsafe_lock);
			ceph_get_cap_refs(ci, CEPH_CAP_FILE_WR);
		}
572
		
573
		ret = ceph_osdc_wait_request(&fsc->client->osdc, req);
574 575 576 577 578 579
		if (ret < 0 && req->r_safe_callback) {
			spin_lock(&ci->i_unsafe_lock);
			list_del_init(&req->r_unsafe_item);
			spin_unlock(&ci->i_unsafe_lock);
			ceph_put_cap_refs(ci, CEPH_CAP_FILE_WR);
		}
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	}

	if (file->f_flags & O_DIRECT)
583
		ceph_put_page_vector(pages, num_pages, false);
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	else if (file->f_flags & O_SYNC)
		ceph_release_page_vector(pages, num_pages);

out:
	ceph_osdc_put_request(req);
	if (ret == 0) {
		pos += len;
		written += len;
		left -= len;
		if (left)
			goto more;

		ret = written;
		*offset = pos;
		if (pos > i_size_read(inode))
			check_caps = ceph_inode_set_size(inode, pos);
		if (check_caps)
			ceph_check_caps(ceph_inode(inode), CHECK_CAPS_AUTHONLY,
					NULL);
	}
	return ret;
}

/*
 * Wrap generic_file_aio_read with checks for cap bits on the inode.
 * Atomically grab references, so that those bits are not released
 * back to the MDS mid-read.
 *
 * Hmm, the sync read case isn't actually async... should it be?
 */
static ssize_t ceph_aio_read(struct kiocb *iocb, const struct iovec *iov,
			     unsigned long nr_segs, loff_t pos)
{
	struct file *filp = iocb->ki_filp;
618
	struct ceph_file_info *fi = filp->private_data;
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	loff_t *ppos = &iocb->ki_pos;
	size_t len = iov->iov_len;
	struct inode *inode = filp->f_dentry->d_inode;
	struct ceph_inode_info *ci = ceph_inode(inode);
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	void __user *base = iov->iov_base;
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	ssize_t ret;
625
	int want, got = 0;
626
	int checkeof = 0, read = 0;
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	dout("aio_read %p %llx.%llx %llu~%u trying to get caps on %p\n",
	     inode, ceph_vinop(inode), pos, (unsigned)len, inode);
630
again:
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	__ceph_do_pending_vmtruncate(inode);
632 633 634 635 636
	if (fi->fmode & CEPH_FILE_MODE_LAZY)
		want = CEPH_CAP_FILE_CACHE | CEPH_CAP_FILE_LAZYIO;
	else
		want = CEPH_CAP_FILE_CACHE;
	ret = ceph_get_caps(ci, CEPH_CAP_FILE_RD, want, &got, -1);
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	if (ret < 0)
		goto out;
	dout("aio_read %p %llx.%llx %llu~%u got cap refs on %s\n",
	     inode, ceph_vinop(inode), pos, (unsigned)len,
	     ceph_cap_string(got));

643
	if ((got & (CEPH_CAP_FILE_CACHE|CEPH_CAP_FILE_LAZYIO)) == 0 ||
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	    (iocb->ki_filp->f_flags & O_DIRECT) ||
	    (inode->i_sb->s_flags & MS_SYNCHRONOUS))
		/* hmm, this isn't really async... */
647
		ret = ceph_sync_read(filp, base, len, ppos, &checkeof);
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	else
		ret = generic_file_aio_read(iocb, iov, nr_segs, pos);

out:
	dout("aio_read %p %llx.%llx dropping cap refs on %s = %d\n",
	     inode, ceph_vinop(inode), ceph_cap_string(got), (int)ret);
	ceph_put_cap_refs(ci, got);
655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671

	if (checkeof && ret >= 0) {
		int statret = ceph_do_getattr(inode, CEPH_STAT_CAP_SIZE);

		/* hit EOF or hole? */
		if (statret == 0 && *ppos < inode->i_size) {
			dout("aio_read sync_read hit hole, reading more\n");
			read += ret;
			base += ret;
			len -= ret;
			checkeof = 0;
			goto again;
		}
	}
	if (ret >= 0)
		ret += read;

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	return ret;
}

/*
 * Take cap references to avoid releasing caps to MDS mid-write.
 *
 * If we are synchronous, and write with an old snap context, the OSD
 * may return EOLDSNAPC.  In that case, retry the write.. _after_
 * dropping our cap refs and allowing the pending snap to logically
 * complete _before_ this write occurs.
 *
 * If we are near ENOSPC, write synchronously.
 */
static ssize_t ceph_aio_write(struct kiocb *iocb, const struct iovec *iov,
		       unsigned long nr_segs, loff_t pos)
{
	struct file *file = iocb->ki_filp;
689
	struct ceph_file_info *fi = file->private_data;
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690 691
	struct inode *inode = file->f_dentry->d_inode;
	struct ceph_inode_info *ci = ceph_inode(inode);
692 693
	struct ceph_osd_client *osdc =
		&ceph_sb_to_client(inode->i_sb)->client->osdc;
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	loff_t endoff = pos + iov->iov_len;
695
	int want, got = 0;
696
	int ret, err;
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	if (ceph_snap(inode) != CEPH_NOSNAP)
		return -EROFS;

retry_snap:
	if (ceph_osdmap_flag(osdc->osdmap, CEPH_OSDMAP_FULL))
		return -ENOSPC;
	__ceph_do_pending_vmtruncate(inode);
	dout("aio_write %p %llx.%llx %llu~%u getting caps. i_size %llu\n",
	     inode, ceph_vinop(inode), pos, (unsigned)iov->iov_len,
	     inode->i_size);
708 709 710 711 712
	if (fi->fmode & CEPH_FILE_MODE_LAZY)
		want = CEPH_CAP_FILE_BUFFER | CEPH_CAP_FILE_LAZYIO;
	else
		want = CEPH_CAP_FILE_BUFFER;
	ret = ceph_get_caps(ci, CEPH_CAP_FILE_WR, want, &got, endoff);
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	if (ret < 0)
		goto out;

	dout("aio_write %p %llx.%llx %llu~%u  got cap refs on %s\n",
	     inode, ceph_vinop(inode), pos, (unsigned)iov->iov_len,
	     ceph_cap_string(got));

720
	if ((got & (CEPH_CAP_FILE_BUFFER|CEPH_CAP_FILE_LAZYIO)) == 0 ||
S
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721 722 723 724 725 726 727 728 729
	    (iocb->ki_filp->f_flags & O_DIRECT) ||
	    (inode->i_sb->s_flags & MS_SYNCHRONOUS)) {
		ret = ceph_sync_write(file, iov->iov_base, iov->iov_len,
			&iocb->ki_pos);
	} else {
		ret = generic_file_aio_write(iocb, iov, nr_segs, pos);

		if ((ret >= 0 || ret == -EIOCBQUEUED) &&
		    ((file->f_flags & O_SYNC) || IS_SYNC(file->f_mapping->host)
730
		     || ceph_osdmap_flag(osdc->osdmap, CEPH_OSDMAP_NEARFULL))) {
731
			err = vfs_fsync_range(file, pos, pos + ret - 1, 1);
732 733 734
			if (err < 0)
				ret = err;
		}
S
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735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816
	}
	if (ret >= 0) {
		spin_lock(&inode->i_lock);
		__ceph_mark_dirty_caps(ci, CEPH_CAP_FILE_WR);
		spin_unlock(&inode->i_lock);
	}

out:
	dout("aio_write %p %llx.%llx %llu~%u  dropping cap refs on %s\n",
	     inode, ceph_vinop(inode), pos, (unsigned)iov->iov_len,
	     ceph_cap_string(got));
	ceph_put_cap_refs(ci, got);

	if (ret == -EOLDSNAPC) {
		dout("aio_write %p %llx.%llx %llu~%u got EOLDSNAPC, retrying\n",
		     inode, ceph_vinop(inode), pos, (unsigned)iov->iov_len);
		goto retry_snap;
	}

	return ret;
}

/*
 * llseek.  be sure to verify file size on SEEK_END.
 */
static loff_t ceph_llseek(struct file *file, loff_t offset, int origin)
{
	struct inode *inode = file->f_mapping->host;
	int ret;

	mutex_lock(&inode->i_mutex);
	__ceph_do_pending_vmtruncate(inode);
	switch (origin) {
	case SEEK_END:
		ret = ceph_do_getattr(inode, CEPH_STAT_CAP_SIZE);
		if (ret < 0) {
			offset = ret;
			goto out;
		}
		offset += inode->i_size;
		break;
	case SEEK_CUR:
		/*
		 * Here we special-case the lseek(fd, 0, SEEK_CUR)
		 * position-querying operation.  Avoid rewriting the "same"
		 * f_pos value back to the file because a concurrent read(),
		 * write() or lseek() might have altered it
		 */
		if (offset == 0) {
			offset = file->f_pos;
			goto out;
		}
		offset += file->f_pos;
		break;
	}

	if (offset < 0 || offset > inode->i_sb->s_maxbytes) {
		offset = -EINVAL;
		goto out;
	}

	/* Special lock needed here? */
	if (offset != file->f_pos) {
		file->f_pos = offset;
		file->f_version = 0;
	}

out:
	mutex_unlock(&inode->i_mutex);
	return offset;
}

const struct file_operations ceph_file_fops = {
	.open = ceph_open,
	.release = ceph_release,
	.llseek = ceph_llseek,
	.read = do_sync_read,
	.write = do_sync_write,
	.aio_read = ceph_aio_read,
	.aio_write = ceph_aio_write,
	.mmap = ceph_mmap,
	.fsync = ceph_fsync,
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Greg Farnum 已提交
817 818
	.lock = ceph_lock,
	.flock = ceph_flock,
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819 820 821 822 823 824
	.splice_read = generic_file_splice_read,
	.splice_write = generic_file_splice_write,
	.unlocked_ioctl = ceph_ioctl,
	.compat_ioctl	= ceph_ioctl,
};