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Commit 4d20c685 authored by Kalpak Shah's avatar Kalpak Shah Committed by Theodore Ts'o
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ext4: fix xattr deadlock 



ext4_xattr_set_handle() eventually ends up calling
ext4_mark_inode_dirty() which tries to expand the inode by shifting
the EAs.  This leads to the xattr_sem being downed again and leading
to a deadlock.

This patch makes sure that if ext4_xattr_set_handle() is in the
call-chain, ext4_mark_inode_dirty() will not expand the inode.

Signed-off-by: default avatarKalpak Shah <kalpak.shah@sun.com>
Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
parent 45a90bfd

fs/ext4/xattr.c

+6 −0
Original line number Diff line number Diff line
@@ -959,6 +959,7 @@ ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index, 
	struct ext4_xattr_block_find bs = {

		.s = { .not_found = -ENODATA, },

	};

	unsigned long no_expand;

	int error;



	if (!name)
@@ -966,6 +967,9 @@ ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index, 
	if (strlen(name) > 255)

		return -ERANGE;

	down_write(&EXT4_I(inode)->xattr_sem);

	no_expand = EXT4_I(inode)->i_state & EXT4_STATE_NO_EXPAND;

	EXT4_I(inode)->i_state |= EXT4_STATE_NO_EXPAND;



	error = ext4_get_inode_loc(inode, &is.iloc);

	if (error)

		goto cleanup;
@@ -1042,6 +1046,8 @@ ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index, 
cleanup:

	brelse(is.iloc.bh);

	brelse(bs.bh);

	if (no_expand == 0)

		EXT4_I(inode)->i_state &= ~EXT4_STATE_NO_EXPAND;

	up_write(&EXT4_I(inode)->xattr_sem);

	return error;

}