linux-toradex.git/fs/notify, branch v5.16

fanotify: Allow users to request FAN_FS_ERROR events

2021-10-27T10:53:45+00:00

Wire up the FAN_FS_ERROR event in the fanotify_mark syscall, allowing
user space to request the monitoring of FAN_FS_ERROR events.

These events are limited to filesystem marks, so check it is the
case in the syscall handler.

Link: https://lore.kernel.org/r/20211025192746.66445-29-krisman@collabora.com
Reviewed-by: Amir Goldstein 
Reviewed-by: Jan Kara 
Signed-off-by: Gabriel Krisman Bertazi 
Signed-off-by: Jan Kara

fanotify: Emit generic error info for error event

2021-10-27T10:53:42+00:00

The error info is a record sent to users on FAN_FS_ERROR events
documenting the type of error.  It also carries an error count,
documenting how many errors were observed since the last reporting.

Link: https://lore.kernel.org/r/20211025192746.66445-28-krisman@collabora.com
Reviewed-by: Amir Goldstein 
Reviewed-by: Jan Kara 
Signed-off-by: Gabriel Krisman Bertazi 
Signed-off-by: Jan Kara

fanotify: Report fid info for file related file system errors

2021-10-27T10:37:20+00:00

Plumb the pieces to add a FID report to error records.  Since all error
event memory must be pre-allocated, we pre-allocate the maximum file
handle size possible, such that it should always fit.

For errors that don't expose a file handle, report it with an invalid
FID. Internally we use zero-length FILEID_ROOT file handle for passing
the information (which we report as zero-length FILEID_INVALID file
handle to userspace) so we update the handle reporting code to deal with
this case correctly.

Link: https://lore.kernel.org/r/20211025192746.66445-27-krisman@collabora.com
Link: https://lore.kernel.org/r/20211025192746.66445-25-krisman@collabora.com
Signed-off-by: Gabriel Krisman Bertazi 
Reviewed-by: Amir Goldstein 
Reviewed-by: Jan Kara 
[Folded two patches into 2 to make series bisectable]
Signed-off-by: Jan Kara

fanotify: WARN_ON against too large file handles

2021-10-27T10:37:20+00:00

struct fanotify_error_event, at least, is preallocated and isn't able to
to handle arbitrarily large file handles.  Future-proof the code by
complaining loudly if a handle larger than MAX_HANDLE_SZ is ever found.

Link: https://lore.kernel.org/r/20211025192746.66445-26-krisman@collabora.com
Reviewed-by: Amir Goldstein 
Reviewed-by: Jan Kara 
Signed-off-by: Gabriel Krisman Bertazi 
Signed-off-by: Jan Kara

fanotify: Add helpers to decide whether to report FID/DFID

2021-10-27T10:37:20+00:00

Now that there is an event that reports FID records even for a zeroed
file handle, wrap the logic that deides whether to issue the records
into helper functions.  This shouldn't have any impact on the code, but
simplifies further patches.

Link: https://lore.kernel.org/r/20211025192746.66445-24-krisman@collabora.com
Reviewed-by: Jan Kara 
Signed-off-by: Gabriel Krisman Bertazi 
Reviewed-by: Amir Goldstein 
Signed-off-by: Jan Kara

fanotify: Wrap object_fh inline space in a creator macro

2021-10-27T10:37:20+00:00

fanotify_error_event would duplicate this sequence of declarations that
already exist elsewhere with a slight different size.  Create a helper
macro to avoid code duplication.

Link: https://lore.kernel.org/r/20211025192746.66445-23-krisman@collabora.com
Suggested-by: Jan Kara 
Reviewed-by: Amir Goldstein 
Reviewed-by: Jan Kara 
Signed-off-by: Gabriel Krisman Bertazi 
Signed-off-by: Jan Kara

fanotify: Support merging of error events

2021-10-27T10:37:13+00:00

Error events (FAN_FS_ERROR) against the same file system can be merged
by simply iterating the error count.  The hash is taken from the fsid,
without considering the FH.  This means that only the first error object
is reported.

Link: https://lore.kernel.org/r/20211025192746.66445-22-krisman@collabora.com
Reviewed-by: Amir Goldstein 
Reviewed-by: Jan Kara 
Signed-off-by: Gabriel Krisman Bertazi 
Signed-off-by: Jan Kara

fanotify: Support enqueueing of error events

2021-10-27T10:35:10+00:00

Once an error event is triggered, enqueue it in the notification group,
similarly to what is done for other events.  FAN_FS_ERROR is not
handled specially, since the memory is now handled by a preallocated
mempool.

For now, make the event unhashed.  A future patch implements merging of
this kind of event.

Link: https://lore.kernel.org/r/20211025192746.66445-21-krisman@collabora.com
Reviewed-by: Jan Kara 
Reviewed-by: Amir Goldstein 
Signed-off-by: Gabriel Krisman Bertazi 
Signed-off-by: Jan Kara

fanotify: Pre-allocate pool of error events

2021-10-27T10:35:05+00:00

Pre-allocate slots for file system errors to have greater chances of
succeeding, since error events can happen in GFP_NOFS context.  This
patch introduces a group-wide mempool of error events, shared by all
FAN_FS_ERROR marks in this group.

Link: https://lore.kernel.org/r/20211025192746.66445-20-krisman@collabora.com
Reviewed-by: Amir Goldstein 
Reviewed-by: Jan Kara 
Signed-off-by: Gabriel Krisman Bertazi 
Signed-off-by: Jan Kara

fanotify: Reserve UAPI bits for FAN_FS_ERROR

2021-10-27T10:34:59+00:00

FAN_FS_ERROR allows reporting of event type FS_ERROR to userspace, which
is a mechanism to report file system wide problems via fanotify.  This
commit preallocate userspace visible bits to match the FS_ERROR event.

Link: https://lore.kernel.org/r/20211025192746.66445-19-krisman@collabora.com
Reviewed-by: Jan Kara 
Reviewed-by: Amir Goldstein 
Signed-off-by: Gabriel Krisman Bertazi 
Signed-off-by: Jan Kara