Just as in ext4_punch_hole() it is important that we block DIO writes
while the truncate is proceeding, since during the overwriting DIO
write, we drop i_mutex, which means a truncate could start while the
Direct I/O operation is still in progress.
Signed-off-by: "Theodore Ts'o" <tytso@xxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
---
fs/ext4/inode.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 98b9bff..3c5edf2 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -3659,12 +3659,16 @@ void ext4_truncate(struct inode *inode)
if (inode->i_size == 0 && !test_opt(inode->i_sb, NO_AUTO_DA_ALLOC))
ext4_set_inode_state(inode, EXT4_STATE_DA_ALLOC_CLOSE);
+ /* Wait all existing dio workers, newcomers will block on i_mutex */
+ ext4_inode_block_unlocked_dio(inode);
+ inode_dio_wait(inode);
+
if (ext4_has_inline_data(inode)) {
int has_inline = 1;
ext4_inline_data_truncate(inode, &has_inline);
if (has_inline)
- return;
+ goto out_resume;
}
if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
@@ -3675,7 +3679,7 @@ void ext4_truncate(struct inode *inode)
handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, credits);
if (IS_ERR(handle)) {
ext4_std_error(inode->i_sb, PTR_ERR(handle));
- return;
+ goto out_resume;
}
if (inode->i_size & (inode->i_sb->s_blocksize - 1))
@@ -3722,6 +3726,8 @@ out_stop:
ext4_mark_inode_dirty(handle, inode);
ext4_journal_stop(handle);
+out_resume:
+ ext4_inode_resume_unlocked_dio(inode);
trace_ext4_truncate_exit(inode);
}
--
1.7.12.rc0.22.gcdd159b
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