From 0390131ba84fd3f726f9e24fc4553828125700bb Mon Sep 17 00:00:00 2001 From: Frank Mayhar Date: Wed, 7 Jan 2009 00:06:22 -0500 Subject: ext4: Allow ext4 to run without a journal A few weeks ago I posted a patch for discussion that allowed ext4 to run without a journal. Since that time I've integrated the excellent comments from Andreas and fixed several serious bugs. We're currently running with this patch and generating some performance numbers against both ext2 (with backported reservations code) and ext4 with and without a journal. It just so happens that running without a journal is slightly faster for most everything. We did iozone -T -t 4 s 2g -r 256k -T -I -i0 -i1 -i2 which creates 4 threads, each of which create and do reads and writes on a 2G file, with a buffer size of 256K, using O_DIRECT for all file opens to bypass the page cache. Results: ext2 ext4, default ext4, no journal initial writes 13.0 MB/s 15.4 MB/s 15.7 MB/s rewrites 13.1 MB/s 15.6 MB/s 15.9 MB/s reads 15.2 MB/s 16.9 MB/s 17.2 MB/s re-reads 15.3 MB/s 16.9 MB/s 17.2 MB/s random readers 5.6 MB/s 5.6 MB/s 5.7 MB/s random writers 5.1 MB/s 5.3 MB/s 5.4 MB/s So it seems that, so far, this was a useful exercise. Signed-off-by: Frank Mayhar Signed-off-by: "Theodore Ts'o" --- fs/ext4/migrate.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'fs/ext4/migrate.c') diff --git a/fs/ext4/migrate.c b/fs/ext4/migrate.c index f2a9cf498ecd..e7cd488da4bb 100644 --- a/fs/ext4/migrate.c +++ b/fs/ext4/migrate.c @@ -59,7 +59,8 @@ static int finish_range(handle_t *handle, struct inode *inode, /* * Make sure the credit we accumalated is not really high */ - if (needed && handle->h_buffer_credits >= EXT4_RESERVE_TRANS_BLOCKS) { + if (needed && ext4_handle_has_enough_credits(handle, + EXT4_RESERVE_TRANS_BLOCKS)) { retval = ext4_journal_restart(handle, needed); if (retval) goto err_out; @@ -229,7 +230,7 @@ static int extend_credit_for_blkdel(handle_t *handle, struct inode *inode) { int retval = 0, needed; - if (handle->h_buffer_credits > EXT4_RESERVE_TRANS_BLOCKS) + if (ext4_handle_has_enough_credits(handle, EXT4_RESERVE_TRANS_BLOCKS+1)) return 0; /* * We are freeing a blocks. During this we touch -- cgit v1.2.2 From 83982b6f47201c4c7767210d24d7d8c99567a0b3 Mon Sep 17 00:00:00 2001 From: Theodore Ts'o Date: Tue, 6 Jan 2009 14:53:16 -0500 Subject: ext4: Remove "extents" mount option This mount option is largely superfluous, and in fact the way it was implemented was buggy; if a filesystem which did not have the extents feature flag was mounted -o extents, the filesystem would attempt to create and use extents-based file even though the extents feature flag was not eabled. The simplest thing to do is to nuke the mount option entirely. It's not all that useful to force the non-creation of new extent-based files if the filesystem can support it. Signed-off-by: "Theodore Ts'o" --- fs/ext4/migrate.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) (limited to 'fs/ext4/migrate.c') diff --git a/fs/ext4/migrate.c b/fs/ext4/migrate.c index e7cd488da4bb..734abca25e35 100644 --- a/fs/ext4/migrate.c +++ b/fs/ext4/migrate.c @@ -459,13 +459,13 @@ int ext4_ext_migrate(struct inode *inode) struct list_blocks_struct lb; unsigned long max_entries; - if (!test_opt(inode->i_sb, EXTENTS)) - /* - * if mounted with noextents we don't allow the migrate - */ - return -EINVAL; - - if ((EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL)) + /* + * If the filesystem does not support extents, or the inode + * already is extent-based, error out. + */ + if (!EXT4_HAS_INCOMPAT_FEATURE(inode->i_sb, + EXT4_FEATURE_INCOMPAT_EXTENTS) || + (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL)) return -EINVAL; if (S_ISLNK(inode->i_mode) && inode->i_blocks == 0) -- cgit v1.2.2