diff mbox series

[v4] cifs: report error instead of invalid when revalidating a dentry fails

Message ID 20210205144248.13508-1-aaptel@suse.com (mailing list archive)
State New, archived
Headers show
Series [v4] cifs: report error instead of invalid when revalidating a dentry fails | expand

Commit Message

Aurélien Aptel Feb. 5, 2021, 2:42 p.m. UTC
From: Aurelien Aptel <aaptel@suse.com>

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>
CC: stable@vger.kernel.org

---
 fs/cifs/dir.c | 22 ++++++++++++++++++++--
 1 file changed, 20 insertions(+), 2 deletions(-)

Comments

Shyam Prasad N Feb. 5, 2021, 2:52 p.m. UTC | #1
Looks good to me.
Maybe change the FYI in the cifs_dbg line above to VFS?

On Fri, Feb 5, 2021 at 6:42 AM Aurélien Aptel <aaptel@suse.com> wrote:
>
> From: Aurelien Aptel <aaptel@suse.com>
>
> 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>
> 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
> --
> 2.29.2
>
Steve French Feb. 5, 2021, 10:31 p.m. UTC | #2
Tentatively merged into cifs-2.6.git for-next, since it seems to have
fixed the problem we saw with test generic/070


On Fri, Feb 5, 2021 at 8:42 AM Aurélien Aptel <aaptel@suse.com> wrote:
>
> From: Aurelien Aptel <aaptel@suse.com>
>
> 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>
> 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
> --
> 2.29.2
>


--
Thanks,

Steve
diff mbox series

Patch

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