btrfs: update comment for struct btrfs_inode::lock

[ Upstream commit 68539bd0e73b457f88a9d00cabb6533ec8582dc9 ]

Update the comment for the lock named "lock" in struct btrfs_inode because
it does not mention that the fields "delalloc_bytes", "defrag_bytes",
"csum_bytes", "outstanding_extents" and "disk_i_size" are also protected
by that lock.

Also add a comment on top of each field protected by this lock to mention
that the lock protects them.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Stable-dep-of: 7ee85f5515e8 ("btrfs: fix race setting file private on concurrent lseek using same fd")
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/fs/btrfs/btrfs_inode.h b/fs/btrfs/btrfs_inode.h
index b75c7f593478042ac1805724d57a4f50fd99799f..e9a979d0a9585672472090ece20adffc6f3d53c1 100644 (file)
--- a/fs/btrfs/btrfs_inode.h
+++ b/fs/btrfs/btrfs_inode.h
@@ -82,8 +82,9 @@ struct btrfs_inode {
        /*
         * Lock for counters and all fields used to determine if the inode is in
         * the log or not (last_trans, last_sub_trans, last_log_commit,
-        * logged_trans), to access/update new_delalloc_bytes and to update the
-        * VFS' inode number of bytes used.
+        * logged_trans), to access/update delalloc_bytes, new_delalloc_bytes,
+        * defrag_bytes, disk_i_size, outstanding_extents, csum_bytes and to
+        * update the VFS' inode number of bytes used.
         */
        spinlock_t lock;
 
@@ -106,7 +107,7 @@ struct btrfs_inode {
         * Counters to keep track of the number of extent item's we may use due
         * to delalloc and such.  outstanding_extents is the number of extent
         * items we think we'll end up using, and reserved_extents is the number
-        * of extent items we've reserved metadata for.
+        * of extent items we've reserved metadata for. Protected by 'lock'.
         */
        unsigned outstanding_extents;
 
@@ -130,28 +131,31 @@ struct btrfs_inode {
        u64 generation;
 
        /*
-        * transid of the trans_handle that last modified this inode
+        * ID of the transaction handle that last modified this inode.
+        * Protected by 'lock'.
         */
        u64 last_trans;
 
        /*
-        * transid that last logged this inode
+        * ID of the transaction that last logged this inode.
+        * Protected by 'lock'.
         */
        u64 logged_trans;
 
        /*
-        * log transid when this inode was last modified
+        * Log transaction ID when this inode was last modified.
+        * Protected by 'lock'.
         */
        int last_sub_trans;
 
-       /* a local copy of root's last_log_commit */
+       /* A local copy of root's last_log_commit. Protected by 'lock'. */
        int last_log_commit;
 
        union {
                /*
                 * Total number of bytes pending delalloc, used by stat to
                 * calculate the real block usage of the file. This is used
-                * only for files.
+                * only for files. Protected by 'lock'.
                 */
                u64 delalloc_bytes;
                /*
@@ -169,7 +173,7 @@ struct btrfs_inode {
                 * Total number of bytes pending delalloc that fall within a file
                 * range that is either a hole or beyond EOF (and no prealloc extent
                 * exists in the range). This is always <= delalloc_bytes and this
-                * is used only for files.
+                * is used only for files. Protected by 'lock'.
                 */
                u64 new_delalloc_bytes;
                /*
@@ -180,15 +184,15 @@ struct btrfs_inode {
        };
 
        /*
-        * total number of bytes pending defrag, used by stat to check whether
-        * it needs COW.
+        * Total number of bytes pending defrag, used by stat to check whether
+        * it needs COW. Protected by 'lock'.
         */
        u64 defrag_bytes;
 
        /*
-        * the size of the file stored in the metadata on disk.  data=ordered
+        * The size of the file stored in the metadata on disk.  data=ordered
         * means the in-memory i_size might be larger than the size on disk
-        * because not all the blocks are written yet.
+        * because not all the blocks are written yet. Protected by 'lock'.
         */
        u64 disk_i_size;
 
@@ -222,7 +226,7 @@ struct btrfs_inode {
 
        /*
         * Number of bytes outstanding that are going to need csums.  This is
-        * used in ENOSPC accounting.
+        * used in ENOSPC accounting. Protected by 'lock'.
         */
        u64 csum_bytes;