ext4: remove extent cache entries when truncating inline data

Conditionally remove all cached extents belonging to an inode
when truncating its inline data.  It's only necessary to attempt to
remove cached extents when a conversion from inline to extent storage
has been initiated (!EXT4_STATE_MAY_INLINE_DATA).  This avoids
unnecessary es lock overhead in the more common inline case.

Signed-off-by: Eric Whitney <enwlinux@gmail.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Link: https://lore.kernel.org/r/20210819144927.25163-2-enwlinux@gmail.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

diff --git a/fs/ext4/inline.c b/fs/ext4/inline.c
index 50a3031bf466d3b3ba546f812915239ec643d2b6..39a1ab129fdc94b2caa18a7febe8a5b0f8ffa7b4 100644 (file)
--- a/fs/ext4/inline.c
+++ b/fs/ext4/inline.c
@@ -7,6 +7,7 @@
 #include <linux/iomap.h>
 #include <linux/fiemap.h>
 #include <linux/iversion.h>
+#include <linux/backing-dev.h>
 
 #include "ext4_jbd2.h"
 #include "ext4.h"
@@ -1918,6 +1919,24 @@ int ext4_inline_data_truncate(struct inode *inode, int *has_inline)
        EXT4_I(inode)->i_disksize = i_size;
 
        if (i_size < inline_size) {
+               /*
+                * if there's inline data to truncate and this file was
+                * converted to extents after that inline data was written,
+                * the extent status cache must be cleared to avoid leaving
+                * behind stale delayed allocated extent entries
+                */
+               if (!ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA)) {
+retry:
+                       err = ext4_es_remove_extent(inode, 0, EXT_MAX_BLOCKS);
+                       if (err == -ENOMEM) {
+                               cond_resched();
+                               congestion_wait(BLK_RW_ASYNC, HZ/50);
+                               goto retry;
+                       }
+                       if (err)
+                               goto out_error;
+               }
+
                /* Clear the content in the xattr space. */
                if (inline_size > EXT4_MIN_INLINE_DATA_SIZE) {
                        if ((err = ext4_xattr_ibody_find(inode, &i, &is)) != 0)