Commit 812c0cab authored Dec 24, 2018 by Theodore Ts'o

ext4: make sure enough credits are reserved for dioread_nolock writes



There are enough credits reserved for most dioread_nolock writes;
however, if the extent tree is sufficiently deep, and/or quota is
enabled, the code was not allowing for all eventualities when
reserving journal credits for the unwritten extent conversion.

This problem can be seen using xfstests ext4/034:

   WARNING: CPU: 1 PID: 257 at fs/ext4/ext4_jbd2.c:271 __ext4_handle_dirty_metadata+0x10c/0x180
   Workqueue: ext4-rsv-conversion ext4_end_io_rsv_work
   RIP: 0010:__ext4_handle_dirty_metadata+0x10c/0x180
   	...
   EXT4-fs: ext4_free_blocks:4938: aborting transaction: error 28 in __ext4_handle_dirty_metadata
   EXT4: jbd2_journal_dirty_metadata failed: handle type 11 started at line 4921, credits 4/0, errcode -28
   EXT4-fs error (device dm-1) in ext4_free_blocks:4950: error 28

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org

parent 18f2c4fc

fs/ext4/inode.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -2778,7 +2778,8 @@ static int ext4_writepages(struct address_space *mapping,
		* We may need to convert up to one extent per block in
		* the page and we may dirty the inode.
		*/
		rsv_blocks = 1 + (PAGE_SIZE >> inode->i_blkbits);
		rsv_blocks = 1 + ext4_chunk_trans_blocks(inode,
		PAGE_SIZE >> inode->i_blkbits);
		}

		/*

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