Eric Sandeen wrote:
Creating many small files in rapid succession on a small filesystem can lead to spurious ENOSPC; on a 104MB filesystem: for i in `seq 1 22500`; do echo -n > $SCRATCH_MNT/$i echo XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX > $SCRATCH_MNT/$i done leads to ENOSPC even though after a sync, 40% of the fs is free again. This is because we reserve worst-case metadata for delalloc writes, and when data is allocated that worst-case reservation was not needed. I've added 2 flushers here: * when free space is low compared to dirty blocks, do an async flush * when we get a hard ENOSPC, do a sync flush before retry This resolves the testcase for me.
argh, but fails xfstests 083 at least: # Exercise filesystem full behaviour - run numerous fsstress # processes in write mode on a small filesystem. NB: delayed # allocate flushing is quite deadlock prone at the filesystem # full boundary due to the fact that we will retry allocation # several times after flushing, before giving back ENOSPC. and indeed I deadlock ;) so don't merge this yet! -Eric
Signed-off-by: Eric Sandeen <sandeen@xxxxxxxxxx> --- diff --git a/fs/ext4/balloc.c b/fs/ext4/balloc.c index 1d04189..63519fc 100644 --- a/fs/ext4/balloc.c +++ b/fs/ext4/balloc.c @@ -605,6 +605,17 @@ int ext4_claim_free_blocks(struct ext4_sb_info *sbi, */ int ext4_should_retry_alloc(struct super_block *sb, int *retries) { + /* try a sync to flush delalloc space & free resvd metadata */ + if (test_opt(sb, DELALLOC) && + *retries == 0 && + !ext4_has_free_blocks(EXT4_SB(sb), 1)) { + down_read(&sb->s_umount); + sync_inodes_sb(sb); + up_read(&sb->s_umount); + (*retries)++; + return 1; + } + if (!ext4_has_free_blocks(EXT4_SB(sb), 1) || (*retries)++ > 3 || !EXT4_SB(sb)->s_journal) diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 5c5bc5d..27c8b9b 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c@@ -3024,11 +3024,18 @@ static int ext4_nonda_switch(struct super_block *sb)if (2 * free_blocks < 3 * dirty_blocks || free_blocks < (dirty_blocks + EXT4_FREEBLOCKS_WATERMARK)) { /* - * free block count is less that 150% of dirty blocks - * or free blocks is less that watermark + * free block count is less than 150% of dirty blocks + * or free blocks is less than watermark */ return 1; } + /* + * Even if we don't switch but are nearing capacity, + * start pushing delalloc when 1/2 of free blocks are dirty. + */ + if (free_blocks < 2 * dirty_blocks) + writeback_inodes_sb(sb); + return 0; } -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
-- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
