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authorJan Kara <jack@suse.cz>2016-08-11 12:38:55 -0400
committerTheodore Ts'o <tytso@mit.edu>2016-08-11 12:38:55 -0400
commit2e81a4eeedcaa66e35f58b81e0755b87057ce392 (patch)
treec51fa9b5eb8a39ec51afcaf836b2a7ad597743cd /fs/ext4
parent443a8c41cd49de66a3fda45b32b9860ea0292b84 (diff)
downloadlinux-2e81a4eeedcaa66e35f58b81e0755b87057ce392.tar.bz2
ext4: avoid deadlock when expanding inode size
When we need to move xattrs into external xattr block, we call ext4_xattr_block_set() from ext4_expand_extra_isize_ea(). That may end up calling ext4_mark_inode_dirty() again which will recurse back into the inode expansion code leading to deadlocks. Protect from recursion using EXT4_STATE_NO_EXPAND inode flag and move its management into ext4_expand_extra_isize_ea() since its manipulation is safe there (due to xattr_sem) from possible races with ext4_xattr_set_handle() which plays with it as well. CC: stable@vger.kernel.org # 4.4.x Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Diffstat (limited to 'fs/ext4')
-rw-r--r--fs/ext4/inode.c2
-rw-r--r--fs/ext4/xattr.c19
2 files changed, 13 insertions, 8 deletions
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 5a6277d80f7c..13c95b290263 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -5466,8 +5466,6 @@ int ext4_mark_inode_dirty(handle_t *handle, struct inode *inode)
sbi->s_want_extra_isize,
iloc, handle);
if (ret) {
- ext4_set_inode_state(inode,
- EXT4_STATE_NO_EXPAND);
if (mnt_count !=
le16_to_cpu(sbi->s_es->s_mnt_count)) {
ext4_warning(inode->i_sb,
diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c
index c893f00b6dc0..2eb935ca5d9e 100644
--- a/fs/ext4/xattr.c
+++ b/fs/ext4/xattr.c
@@ -1358,12 +1358,14 @@ int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
int isize_diff; /* How much do we need to grow i_extra_isize */
down_write(&EXT4_I(inode)->xattr_sem);
+ /*
+ * Set EXT4_STATE_NO_EXPAND to avoid recursion when marking inode dirty
+ */
+ ext4_set_inode_state(inode, EXT4_STATE_NO_EXPAND);
retry:
isize_diff = new_extra_isize - EXT4_I(inode)->i_extra_isize;
- if (EXT4_I(inode)->i_extra_isize >= new_extra_isize) {
- up_write(&EXT4_I(inode)->xattr_sem);
- return 0;
- }
+ if (EXT4_I(inode)->i_extra_isize >= new_extra_isize)
+ goto out;
header = IHDR(inode, raw_inode);
entry = IFIRST(header);
@@ -1392,8 +1394,7 @@ retry:
(void *)header, total_ino,
inode->i_sb->s_blocksize);
EXT4_I(inode)->i_extra_isize = new_extra_isize;
- error = 0;
- goto cleanup;
+ goto out;
}
/*
@@ -1553,6 +1554,8 @@ retry:
kfree(bs);
}
brelse(bh);
+out:
+ ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND);
up_write(&EXT4_I(inode)->xattr_sem);
return 0;
@@ -1564,6 +1567,10 @@ cleanup:
kfree(is);
kfree(bs);
brelse(bh);
+ /*
+ * We deliberately leave EXT4_STATE_NO_EXPAND set here since inode
+ * size expansion failed.
+ */
up_write(&EXT4_I(inode)->xattr_sem);
return error;
}