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Commit 5b41395f authored by Yongqiang Yang's avatar Yongqiang Yang Committed by Theodore Ts'o
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ext4: fix credits computing for indirect mapped files 



When writing a contiguous set of blocks, two indirect blocks could be
needed depending on how the blocks are aligned, so we need to increase
the number of credits needed by one.

[ Also fixed a another bug which could further underestimate the
  number of journal credits needed by 1; the code was using integer
  division instead of DIV_ROUND_UP() -- tytso]

Signed-off-by: default avatarYongqiang Yang <xiaoqiangnk@gmail.com>
Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
Cc: stable@kernel.org
parent 21f97697

fs/ext4/inode.c

+5 −6
Original line number Diff line number Diff line
@@ -5398,13 +5398,12 @@ static int ext4_indirect_trans_blocks(struct inode *inode, int nrblocks, 
	/* if nrblocks are contiguous */

	if (chunk) {

		/*

		 * With N contiguous data blocks, it need at most

		 * N/EXT4_ADDR_PER_BLOCK(inode->i_sb) indirect blocks

		 * 2 dindirect blocks

		 * 1 tindirect block

		 * With N contiguous data blocks, we need at most

		 * N/EXT4_ADDR_PER_BLOCK(inode->i_sb) + 1 indirect blocks,

		 * 2 dindirect blocks, and 1 tindirect block

		 */

		indirects = nrblocks / EXT4_ADDR_PER_BLOCK(inode->i_sb);

		return indirects + 3;

		return DIV_ROUND_UP(nrblocks,

				    EXT4_ADDR_PER_BLOCK(inode->i_sb)) + 4;

	}

	/*

	 * if nrblocks are not contiguous, worse case, each block touch