2015-12-30 16:12:03

by Trond Myklebust

[permalink] [raw]
Subject: [PATCH v2] NFS: Fix attribute cache revalidation

If a NFSv4 client uses the cache_consistency_bitmask in order to
request only information about the change attribute, timestamps and
size, then it has not revalidated all attributes, and hence the
attribute timeout timestamp should not be updated.

Reported-by: Donald Buczek <[email protected]>
Cc: [email protected]
Signed-off-by: Trond Myklebust <[email protected]>
---
V2:
* Fix space borkage
* Always update nfsi->attrtimeo_timestamp on successful revalidation

fs/nfs/inode.c | 54 +++++++++++++++++++++++++++++++++++++++---------------
1 file changed, 39 insertions(+), 15 deletions(-)

diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index c7e8b87da5b2..3e2071a177fd 100644
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -1641,6 +1641,7 @@ static int nfs_update_inode(struct inode *inode, struct nfs_fattr *fattr)
unsigned long invalid = 0;
unsigned long now = jiffies;
unsigned long save_cache_validity;
+ bool cache_revalidated = true;

dfprintk(VFS, "NFS: %s(%s/%lu fh_crc=0x%08x ct=%d info=0x%x)\n",
__func__, inode->i_sb->s_id, inode->i_ino,
@@ -1702,22 +1703,28 @@ static int nfs_update_inode(struct inode *inode, struct nfs_fattr *fattr)
nfs_force_lookup_revalidate(inode);
inode->i_version = fattr->change_attr;
}
- } else
+ } else {
nfsi->cache_validity |= save_cache_validity;
+ cache_revalidated = false;
+ }

if (fattr->valid & NFS_ATTR_FATTR_MTIME) {
memcpy(&inode->i_mtime, &fattr->mtime, sizeof(inode->i_mtime));
- } else if (server->caps & NFS_CAP_MTIME)
+ } else if (server->caps & NFS_CAP_MTIME) {
nfsi->cache_validity |= save_cache_validity &
(NFS_INO_INVALID_ATTR
| NFS_INO_REVAL_FORCED);
+ cache_revalidated = false;
+ }

if (fattr->valid & NFS_ATTR_FATTR_CTIME) {
memcpy(&inode->i_ctime, &fattr->ctime, sizeof(inode->i_ctime));
- } else if (server->caps & NFS_CAP_CTIME)
+ } else if (server->caps & NFS_CAP_CTIME) {
nfsi->cache_validity |= save_cache_validity &
(NFS_INO_INVALID_ATTR
| NFS_INO_REVAL_FORCED);
+ cache_revalidated = false;
+ }

/* Check if our cached file size is stale */
if (fattr->valid & NFS_ATTR_FATTR_SIZE) {
@@ -1737,19 +1744,23 @@ static int nfs_update_inode(struct inode *inode, struct nfs_fattr *fattr)
(long long)cur_isize,
(long long)new_isize);
}
- } else
+ } else {
nfsi->cache_validity |= save_cache_validity &
(NFS_INO_INVALID_ATTR
| NFS_INO_REVAL_PAGECACHE
| NFS_INO_REVAL_FORCED);
+ cache_revalidated = false;
+ }


if (fattr->valid & NFS_ATTR_FATTR_ATIME)
memcpy(&inode->i_atime, &fattr->atime, sizeof(inode->i_atime));
- else if (server->caps & NFS_CAP_ATIME)
+ else if (server->caps & NFS_CAP_ATIME) {
nfsi->cache_validity |= save_cache_validity &
(NFS_INO_INVALID_ATIME
| NFS_INO_REVAL_FORCED);
+ cache_revalidated = false;
+ }

if (fattr->valid & NFS_ATTR_FATTR_MODE) {
if ((inode->i_mode & S_IALLUGO) != (fattr->mode & S_IALLUGO)) {
@@ -1758,36 +1769,42 @@ static int nfs_update_inode(struct inode *inode, struct nfs_fattr *fattr)
inode->i_mode = newmode;
invalid |= NFS_INO_INVALID_ATTR|NFS_INO_INVALID_ACCESS|NFS_INO_INVALID_ACL;
}
- } else if (server->caps & NFS_CAP_MODE)
+ } else if (server->caps & NFS_CAP_MODE) {
nfsi->cache_validity |= save_cache_validity &
(NFS_INO_INVALID_ATTR
| NFS_INO_INVALID_ACCESS
| NFS_INO_INVALID_ACL
| NFS_INO_REVAL_FORCED);
+ cache_revalidated = false;
+ }

if (fattr->valid & NFS_ATTR_FATTR_OWNER) {
if (!uid_eq(inode->i_uid, fattr->uid)) {
invalid |= NFS_INO_INVALID_ATTR|NFS_INO_INVALID_ACCESS|NFS_INO_INVALID_ACL;
inode->i_uid = fattr->uid;
}
- } else if (server->caps & NFS_CAP_OWNER)
+ } else if (server->caps & NFS_CAP_OWNER) {
nfsi->cache_validity |= save_cache_validity &
(NFS_INO_INVALID_ATTR
| NFS_INO_INVALID_ACCESS
| NFS_INO_INVALID_ACL
| NFS_INO_REVAL_FORCED);
+ cache_revalidated = false;
+ }

if (fattr->valid & NFS_ATTR_FATTR_GROUP) {
if (!gid_eq(inode->i_gid, fattr->gid)) {
invalid |= NFS_INO_INVALID_ATTR|NFS_INO_INVALID_ACCESS|NFS_INO_INVALID_ACL;
inode->i_gid = fattr->gid;
}
- } else if (server->caps & NFS_CAP_OWNER_GROUP)
+ } else if (server->caps & NFS_CAP_OWNER_GROUP) {
nfsi->cache_validity |= save_cache_validity &
(NFS_INO_INVALID_ATTR
| NFS_INO_INVALID_ACCESS
| NFS_INO_INVALID_ACL
| NFS_INO_REVAL_FORCED);
+ cache_revalidated = false;
+ }

if (fattr->valid & NFS_ATTR_FATTR_NLINK) {
if (inode->i_nlink != fattr->nlink) {
@@ -1796,19 +1813,22 @@ static int nfs_update_inode(struct inode *inode, struct nfs_fattr *fattr)
invalid |= NFS_INO_INVALID_DATA;
set_nlink(inode, fattr->nlink);
}
- } else if (server->caps & NFS_CAP_NLINK)
+ } else if (server->caps & NFS_CAP_NLINK) {
nfsi->cache_validity |= save_cache_validity &
(NFS_INO_INVALID_ATTR
| NFS_INO_REVAL_FORCED);
+ cache_revalidated = false;
+ }

if (fattr->valid & NFS_ATTR_FATTR_SPACE_USED) {
/*
* report the blocks in 512byte units
*/
inode->i_blocks = nfs_calc_block_size(fattr->du.nfs3.used);
- }
- if (fattr->valid & NFS_ATTR_FATTR_BLOCKS_USED)
+ } else if (fattr->valid & NFS_ATTR_FATTR_BLOCKS_USED)
inode->i_blocks = fattr->du.nfs2.blocks;
+ else
+ cache_revalidated = false;

/* Update attrtimeo value if we're out of the unstable period */
if (invalid & NFS_INO_INVALID_ATTR) {
@@ -1818,9 +1838,13 @@ static int nfs_update_inode(struct inode *inode, struct nfs_fattr *fattr)
/* Set barrier to be more recent than all outstanding updates */
nfsi->attr_gencount = nfs_inc_attr_generation_counter();
} else {
- if (!time_in_range_open(now, nfsi->attrtimeo_timestamp, nfsi->attrtimeo_timestamp + nfsi->attrtimeo)) {
- if ((nfsi->attrtimeo <<= 1) > NFS_MAXATTRTIMEO(inode))
- nfsi->attrtimeo = NFS_MAXATTRTIMEO(inode);
+ if (cache_revalidated) {
+ if (!time_in_range_open(now, nfsi->attrtimeo_timestamp,
+ nfsi->attrtimeo_timestamp + nfsi->attrtimeo)) {
+ nfsi->attrtimeo <<= 1;
+ if (nfsi->attrtimeo > NFS_MAXATTRTIMEO(inode))
+ nfsi->attrtimeo = NFS_MAXATTRTIMEO(inode);
+ }
nfsi->attrtimeo_timestamp = now;
}
/* Set the barrier to be more recent than this fattr */
@@ -1829,7 +1853,7 @@ static int nfs_update_inode(struct inode *inode, struct nfs_fattr *fattr)
}

/* Don't declare attrcache up to date if there were no attrs! */
- if (fattr->valid != 0)
+ if (cache_revalidated)
invalid &= ~NFS_INO_INVALID_ATTR;

/* Don't invalidate the data if we were to blame */
--
2.5.0



2016-01-02 16:19:42

by Donald Buczek

[permalink] [raw]
Subject: Re: [PATCH v2] NFS: Fix attribute cache revalidation

Though I don't understand the caching code, this one works for me, too.

Together with "NFS: Ensure we revalidate attributes before using
execute_ok()" and "NFSv4: Don't perform cached access checks before
we've OPENed the file" it fixes
https://bugzilla.kernel.org/show_bug.cgi?id=109771

Correctly succeeds or fails after change of x-bit on server.

Regards
Donald

--
Donald Buczek
[email protected]
Tel: +49 30 8413 1433