2021-10-25 19:35:46

by Gabriel Krisman Bertazi

[permalink] [raw]
Subject: [PATCH v9 26/31] fanotify: Report fid info for file related file system errors

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.

Reviewed-by: Amir Goldstein <[email protected]>
Reviewed-by: Jan Kara <[email protected]>
Signed-off-by: Gabriel Krisman Bertazi <[email protected]>

---
Changes since v8:
- Drop comment (Amir)
- Move report dereference till after null check (jan)
- Move has_object_fh hunk to earlier patch (jan)
Changes since v7:
- Move WARN_ON to separate patch (Amir)
- Avoid duplication in the structure definition (Amir)
Changes since v6:
- pass fsid from handle_events
Changes since v5:
- Use preallocated MAX_HANDLE_SZ FH buffer
- Report superblock errors with a zerolength INVALID FID (jan, amir)
---
fs/notify/fanotify/fanotify.c | 11 +++++++++++
fs/notify/fanotify/fanotify.h | 6 ++++++
2 files changed, 17 insertions(+)

diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c
index 45df610debbe..465f07e70e6d 100644
--- a/fs/notify/fanotify/fanotify.c
+++ b/fs/notify/fanotify/fanotify.c
@@ -609,7 +609,9 @@ static struct fanotify_event *fanotify_alloc_error_event(
{
struct fs_error_report *report =
fsnotify_data_error_report(data, data_type);
+ struct inode *inode;
struct fanotify_error_event *fee;
+ int fh_len;

if (WARN_ON_ONCE(!report))
return NULL;
@@ -622,6 +624,15 @@ static struct fanotify_event *fanotify_alloc_error_event(
fee->err_count = 1;
fee->fsid = *fsid;

+ inode = report->inode;
+ fh_len = fanotify_encode_fh_len(inode);
+
+ /* Bad fh_len. Fallback to using an invalid fh. Should never happen. */
+ if (!fh_len && inode)
+ inode = NULL;
+
+ fanotify_encode_fh(&fee->object_fh, inode, fh_len, NULL, 0);
+
*hash ^= fanotify_hash_fsid(fsid);

return &fee->fae;
diff --git a/fs/notify/fanotify/fanotify.h b/fs/notify/fanotify/fanotify.h
index f51ab6e556e8..edd7587adcc5 100644
--- a/fs/notify/fanotify/fanotify.h
+++ b/fs/notify/fanotify/fanotify.h
@@ -208,6 +208,8 @@ struct fanotify_error_event {
u32 err_count; /* Suppressed errors count */

__kernel_fsid_t fsid; /* FSID this error refers to. */
+
+ FANOTIFY_INLINE_FH(object_fh, MAX_HANDLE_SZ);
};

static inline struct fanotify_error_event *
@@ -222,6 +224,8 @@ static inline __kernel_fsid_t *fanotify_event_fsid(struct fanotify_event *event)
return &FANOTIFY_FE(event)->fsid;
else if (event->type == FANOTIFY_EVENT_TYPE_FID_NAME)
return &FANOTIFY_NE(event)->fsid;
+ else if (event->type == FANOTIFY_EVENT_TYPE_FS_ERROR)
+ return &FANOTIFY_EE(event)->fsid;
else
return NULL;
}
@@ -233,6 +237,8 @@ static inline struct fanotify_fh *fanotify_event_object_fh(
return &FANOTIFY_FE(event)->object_fh;
else if (event->type == FANOTIFY_EVENT_TYPE_FID_NAME)
return fanotify_info_file_fh(&FANOTIFY_NE(event)->info);
+ else if (event->type == FANOTIFY_EVENT_TYPE_FS_ERROR)
+ return &FANOTIFY_EE(event)->object_fh;
else
return NULL;
}
--
2.33.0