From: Aurelien Aptel aaptel@suse.com
stable inclusion from linux-4.19.175 commit 613fa1fb62c82e6b9c170b7de6f8c8c850624f5a
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commit 21b200d091826a83aafc95d847139b2b0582f6d1 upstream.
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 aaptel@suse.com Suggested-by: Shyam Prasad N nspmangalore@gmail.com Reviewed-by: Shyam Prasad N nspmangalore@gmail.com CC: stable@vger.kernel.org Signed-off-by: Steve French stfrench@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Yang Yingliang yangyingliang@huawei.com Signed-off-by: Cheng Jian cj.chengjian@huawei.com --- 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 f6e3c0089825..c7e162c9383d 100644 --- a/fs/cifs/dir.c +++ b/fs/cifs/dir.c @@ -840,6 +840,7 @@ static int cifs_d_revalidate(struct dentry *direntry, unsigned int flags) { struct inode *inode; + int rc;
if (flags & LOOKUP_RCU) return -ECHILD; @@ -849,8 +850,25 @@ 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