This is a slight variation on a patch previously proposed by Neil Brown
that never got merged.
Prior to commit 5ceb9d7fdaaf ("NFS: Refactor nfs_lookup_revalidate()"),
any error from nfs_lookup_verify_inode() other than -ESTALE would result
in nfs_lookup_revalidate() returning that error (-ESTALE is mapped to
zero).
Since that commit, all errors result in nfs_lookup_revalidate()
returning zero, resulting in dentries being invalidated where they
previously were not (particularly in the case of -ERESTARTSYS).
Fix it by passing the actual error code to nfs_lookup_revalidate_done(),
and leaving the decision on whether to map the error code to zero or
one to nfs_lookup_revalidate_done().
A simple reproducer is to run the following python code in a
subdirectory of an NFS mount (not in the root of the NFS mount):
---8<---
import os
import multiprocessing
import time
if __name__=="__main__":
multiprocessing.set_start_method("spawn")
count = 0
while True:
try:
os.getcwd()
pool = multiprocessing.Pool(10)
pool.close()
pool.terminate()
count += 1
except Exception as e:
print(f"Failed after {count} iterations")
print(e)
break
---8<---
Prior to commit 5ceb9d7fdaaf, the above code would run indefinitely.
After commit 5ceb9d7fdaaf, it fails almost immediately with -ENOENT.
Signed-off-by: Scott Mayhew <smayhew@xxxxxxxxxx>
---
fs/nfs/dir.c | 24 +++++++++++-------------
1 file changed, 11 insertions(+), 13 deletions(-)
diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index ac505671efbd..d9264ed4ac52 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -1635,6 +1635,14 @@ nfs_lookup_revalidate_done(struct inode *dir, struct dentry *dentry,
if (inode && IS_ROOT(dentry))
error = 1;
break;
+ case -ESTALE:
+ case -ENOENT:
+ error = 0;
+ break;
+ case -ETIMEDOUT:
+ if (NFS_SERVER(inode)->flags & NFS_MOUNT_SOFTREVAL)
+ error = 1;
+ break;
}
trace_nfs_lookup_revalidate_exit(dir, dentry, 0, error);
return error;
@@ -1680,18 +1688,8 @@ static int nfs_lookup_revalidate_dentry(struct inode *dir,
dir_verifier = nfs_save_change_attribute(dir);
ret = NFS_PROTO(dir)->lookup(dir, dentry, fhandle, fattr);
- if (ret < 0) {
- switch (ret) {
- case -ESTALE:
- case -ENOENT:
- ret = 0;
- break;
- case -ETIMEDOUT:
- if (NFS_SERVER(inode)->flags & NFS_MOUNT_SOFTREVAL)
- ret = 1;
- }
+ if (ret < 0)
goto out;
- }
/* Request help from readdirplus */
nfs_lookup_advise_force_readdirplus(dir, flags);
@@ -1735,7 +1733,7 @@ nfs_do_lookup_revalidate(struct inode *dir, struct dentry *dentry,
unsigned int flags)
{
struct inode *inode;
- int error;
+ int error = 0;
nfs_inc_stats(dir, NFSIOS_DENTRYREVALIDATE);
inode = d_inode(dentry);
@@ -1780,7 +1778,7 @@ nfs_do_lookup_revalidate(struct inode *dir, struct dentry *dentry,
out_bad:
if (flags & LOOKUP_RCU)
return -ECHILD;
- return nfs_lookup_revalidate_done(dir, dentry, inode, 0);
+ return nfs_lookup_revalidate_done(dir, dentry, inode, error);
}
static int
--
2.44.0
