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fuse: use iversion for readdir cache verification

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Use the internal iversion counter to make sure modifications of the
directory through this filesystem are not missed by the mtime check (due to
mtime granularity).

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
This commit is contained in:
Miklos Szeredi 2018-10-01 10:07:05 +02:00
parent 7118883b44
commit 261aaba72f
3 changed files with 21 additions and 8 deletions
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21
fs/fuse/dir.c
View File

@ -14,6 +14,7 @@
#include <linux/namei.h>
#include <linux/slab.h>
#include <linux/xattr.h>
#include <linux/iversion.h>
#include <linux/posix_acl.h>
static void fuse_advise_use_readdirplus(struct inode *dir)
@ -89,6 +90,12 @@ void fuse_invalidate_attr(struct inode *inode)
get_fuse_inode(inode)->i_time = 0;
}
static void fuse_dir_changed(struct inode *dir)
{
fuse_invalidate_attr(dir);
inode_maybe_inc_iversion(dir, false);
}
/**
* Mark the attributes as stale due to an atime change. Avoid the invalidate if
* atime is not used.
@ -447,7 +454,7 @@ static int fuse_create_open(struct inode *dir, struct dentry *entry,
kfree(forget);
d_instantiate(entry, inode);
fuse_change_entry_timeout(entry, &outentry);
fuse_invalidate_attr(dir);
fuse_dir_changed(dir);
err = finish_open(file, entry, generic_file_open);
if (err) {
fuse_sync_release(ff, flags);
@ -561,7 +568,7 @@ static int create_new_entry(struct fuse_conn *fc, struct fuse_args *args,
} else {
fuse_change_entry_timeout(entry, &outarg);
}
fuse_invalidate_attr(dir);
fuse_dir_changed(dir);
return 0;
out_put_forget_req:
@ -671,7 +678,7 @@ static int fuse_unlink(struct inode *dir, struct dentry *entry)
drop_nlink(inode);
spin_unlock(&fc->lock);
fuse_invalidate_attr(inode);
fuse_invalidate_attr(dir);
fuse_dir_changed(dir);
fuse_invalidate_entry_cache(entry);
fuse_update_ctime(inode);
} else if (err == -EINTR)
@ -693,7 +700,7 @@ static int fuse_rmdir(struct inode *dir, struct dentry *entry)
err = fuse_simple_request(fc, &args);
if (!err) {
clear_nlink(d_inode(entry));
fuse_invalidate_attr(dir);
fuse_dir_changed(dir);
fuse_invalidate_entry_cache(entry);
} else if (err == -EINTR)
fuse_invalidate_entry(entry);
@ -732,9 +739,9 @@ static int fuse_rename_common(struct inode *olddir, struct dentry *oldent,
fuse_update_ctime(d_inode(newent));
}
fuse_invalidate_attr(olddir);
fuse_dir_changed(olddir);
if (olddir != newdir)
fuse_invalidate_attr(newdir);
fuse_dir_changed(newdir);
/* newent will end up negative */
if (!(flags & RENAME_EXCHANGE) && d_really_is_positive(newent)) {
@ -967,7 +974,7 @@ int fuse_reverse_inval_entry(struct super_block *sb, u64 parent_nodeid,
if (!entry)
goto unlock;
fuse_invalidate_attr(parent);
fuse_dir_changed(parent);
fuse_invalidate_entry(entry);
if (child_nodeid != 0 && d_really_is_positive(entry)) {

3
fs/fuse/fuse_i.h
View File

@ -120,6 +120,9 @@ struct fuse_inode {
/* modification time of directory when cache was started */
struct timespec64 mtime;
/* iversion of directory when cache was started */
u64 iversion;
/* protects above fields */
spinlock_t lock;
} rdc;

5
fs/fuse/readdir.c
View File

@ -8,6 +8,7 @@
#include "fuse_i.h"
#include <linux/iversion.h>
#include <linux/posix_acl.h>
#include <linux/pagemap.h>
#include <linux/highmem.h>
@ -447,6 +448,7 @@ retry_locked:
/* Starting cache? Set cache mtime. */
if (!ctx->pos && !fi->rdc.size) {
fi->rdc.mtime = inode->i_mtime;
fi->rdc.iversion = inode_query_iversion(inode);
}
spin_unlock(&fi->rdc.lock);
return UNCACHED;
@ -457,7 +459,8 @@ retry_locked:
* changed, and reset the cache if so.
*/
if (!ctx->pos) {
if (!timespec64_equal(&fi->rdc.mtime, &inode->i_mtime)) {
if (inode_peek_iversion(inode) != fi->rdc.iversion ||
!timespec64_equal(&fi->rdc.mtime, &inode->i_mtime)) {
fuse_rdc_reset(inode);
goto retry_locked;
}