[PATCH v4] cifs: report error instead of invalid when revalidating a dentry fails
From: Aurélien Aptel <hidden>
Date: 2021-02-05 20:26:58
Also in:
linux-fsdevel, stable
Subsystem:
filesystems (vfs and infrastructure), the rest · Maintainers:
Alexander Viro, Christian Brauner, Linus Torvalds
From: Aurelien Aptel <redacted> Assuming - //HOST/a is mounted on /mnt - //HOST/b is mounted on /mnt/b On a slow connection, running 'df' and killing it while it's processing /mnt/b can make cifs_get_inode_info() returns -ERESTARTSYS. This triggers the following chain of events: => the dentry revalidation fail => dentry is put and released => superblock associated with the dentry is put => /mnt/b is unmounted This patch makes cifs_d_revalidate() return the error instead of 0 (invalid) when cifs_revalidate_dentry() fails, except for ENOENT (file deleted) and ESTALE (file recreated). Signed-off-by: Aurelien Aptel <redacted> Suggested-by: Shyam Prasad N <redacted> CC: stable@vger.kernel.org --- fs/cifs/dir.c | 22 ++++++++++++++++++++-- 1 file changed, 20 insertions(+), 2 deletions(-)
diff --git a/fs/cifs/dir.c b/fs/cifs/dir.c
index 68900f1629bff..97ac363b5df16 100644
--- a/fs/cifs/dir.c
+++ b/fs/cifs/dir.c@@ -737,6 +737,7 @@ static int cifs_d_revalidate(struct dentry *direntry, unsigned int flags) { struct inode *inode; + int rc; if (flags & LOOKUP_RCU) return -ECHILD;
@@ -746,8 +747,25 @@ cifs_d_revalidate(struct dentry *direntry, unsigned int flags) if ((flags & LOOKUP_REVAL) && !CIFS_CACHE_READ(CIFS_I(inode))) CIFS_I(inode)->time = 0; /* force reval */ - if (cifs_revalidate_dentry(direntry)) - return 0; + rc = cifs_revalidate_dentry(direntry); + if (rc) { + cifs_dbg(FYI, "cifs_revalidate_dentry failed with rc=%d", rc); + switch (rc) { + case -ENOENT: + case -ESTALE: + /* + * Those errors mean the dentry is invalid + * (file was deleted or recreated) + */ + return 0; + default: + /* + * Otherwise some unexpected error happened + * report it as-is to VFS layer + */ + return rc; + } + } else { /* * If the inode wasn't known to be a dfs entry when
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2.29.2