linux/fs/afs/write.c, branch v3.2.18

fs: push i_mutex and filemap_write_and_wait down into ->fsync() handlers

2011-07-21T00:47:59Z

Btrfs needs to be able to control how filemap_write_and_wait_range() is called in fsync to make it less of a painful operation, so push down taking i_mutex and the calling of filemap_write_and_wait() down into the ->fsync() handlers. Some file systems can drop taking the i_mutex altogether it seems, like ext3 and ocfs2. For correctness sake I just pushed everything down in all cases to make sure that we keep the current behavior the same for everybody, and then each individual fs maintainer can make up their mind about what to do from there. Thanks, Acked-by: Jan Kara Signed-off-by: Josef Bacik Signed-off-by: Al Viro

afs: afs_fill_page reads too much, or wrong data

2011-06-16T15:44:46Z

afs_fill_page should read the page that is about to be written but the current implementation has a number of issues. If we aren't extending the file we always read PAGE_CACHE_SIZE at offset 0. If we are extending the file we try to read the entire file. Change afs_fill_page to read PAGE_CACHE_SIZE at the right offset, clamped to i_size. While here, avoid calling afs_fill_page when we are doing a PAGE_CACHE_SIZE write. Signed-off-by: Anton Blanchard Signed-off-by: David Howells Signed-off-by: Al Viro

afs: Fix oops in afs_unlink_writeback

2011-02-25T19:12:37Z

I'm seeing the following oops when testing afs: Unable to handle kernel paging request for data at address 0x00000008 ... NIP [c0000000003393b0] .afs_unlink_writeback+0x38/0xc0 LR [c00000000033987c] .afs_put_writeback+0x98/0xec Call Trace: [c00000000345f600] [c00000000033987c] .afs_put_writeback+0x98/0xec [c00000000345f690] [c00000000033ae80] .afs_write_begin+0x6a4/0x75c [c00000000345f790] [c00000000012b77c] .generic_file_buffered_write+0x148/0x320 [c00000000345f8d0] [c00000000012e1b8] .__generic_file_aio_write+0x37c/0x3e4 [c00000000345f9d0] [c00000000012e2a8] .generic_file_aio_write+0x88/0xfc [c00000000345fa90] [c0000000003390a8] .afs_file_write+0x10c/0x178 [c00000000345fb40] [c000000000188788] .do_sync_write+0xc4/0x128 [c00000000345fcc0] [c000000000189658] .vfs_write+0xe8/0x1d8 [c00000000345fd70] [c000000000189884] .SyS_write+0x68/0xb0 [c00000000345fe30] [c000000000008564] syscall_exit+0x0/0x40 afs_write_begin hits an error and calls afs_unlink_writeback. In there we do list_del_init on an uninitialised list. The patch below initialises ->link when creating the afs_writeback struct. Signed-off-by: Anton Blanchard Signed-off-by: David Howells Signed-off-by: Linus Torvalds

writeback: remove nonblocking/encountered_congestion references

2010-10-26T23:52:05Z

This removes more dead code that was somehow missed by commit 0d99519efef (writeback: remove unused nonblocking and congestion checks). There are no behavior change except for the removal of two entries from one of the ext4 tracing interface. The nonblocking checks in ->writepages are no longer used because the flusher now prefer to block on get_request_wait() than to skip inodes on IO congestion. The latter will lead to more seeky IO. The nonblocking checks in ->writepage are no longer used because it's redundant with the WB_SYNC_NONE check. We no long set ->nonblocking in VM page out and page migration, because a) it's effectively redundant with WB_SYNC_NONE in current code b) it's old semantic of "Don't get stuck on request queues" is mis-behavior: that would skip some dirty inodes on congestion and page out others, which is unfair in terms of LRU age. Inspired by Christoph Hellwig. Thanks! Signed-off-by: Wu Fengguang Cc: Theodore Ts'o Cc: David Howells Cc: Sage Weil Cc: Steve French Cc: Chris Mason Cc: Jens Axboe Cc: Christoph Hellwig Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

writeback: remove writeback_inodes_wbc

2010-07-06T06:54:03Z

This was just an odd wrapper around writeback_inodes_wb. Removing this also allows to get rid of the bdi member of struct writeback_control which was rather out of place there. Signed-off-by: Christoph Hellwig Signed-off-by: Jens Axboe

drop unused dentry argument to ->fsync

2010-05-28T02:05:02Z

Signed-off-by: Christoph Hellwig Signed-off-by: Al Viro

make sure data is on disk before calling ->write_inode

2010-03-05T18:25:10Z

Similar to the fsync issue fixed a while ago in commit 2daea67e966dc0c42067ebea015ddac6834cef88 we need to write for data to actually hit the disk before writing out the metadata to guarantee data integrity for filesystems that modify the inode in the data I/O completion path. Currently XFS and NFS handle this manually, and AFS has a write_inode method that does nothing but waiting for data, while others are possibly missing out on this. Fortunately this change has a lot less impact than the fsync change as none of the write_inode methods starts data writeout of any form by itself. Signed-off-by: Christoph Hellwig Signed-off-by: Al Viro

afs: remove manual O_SYNC handling

2009-12-10T14:02:50Z

generic_file_aio_write already calls into ->fsync to handle O_SYNC/O_DSYNC. Remove the duplicate manual invocation. Signed-off-by: Christoph Hellwig Signed-off-by: Jan Kara

vfs: Implement proper O_SYNC semantics

2009-12-10T14:02:50Z

While Linux provided an O_SYNC flag basically since day 1, it took until Linux 2.4.0-test12pre2 to actually get it implemented for filesystems, since that day we had generic_osync_around with only minor changes and the great "For now, when the user asks for O_SYNC, we'll actually give O_DSYNC" comment. This patch intends to actually give us real O_SYNC semantics in addition to the O_DSYNC semantics. After Jan's O_SYNC patches which are required before this patch it's actually surprisingly simple, we just need to figure out when to set the datasync flag to vfs_fsync_range and when not. This patch renames the existing O_SYNC flag to O_DSYNC while keeping it's numerical value to keep binary compatibility, and adds a new real O_SYNC flag. To guarantee backwards compatiblity it is defined as expanding to both the O_DSYNC and the new additional binary flag (__O_SYNC) to make sure we are backwards-compatible when compiled against the new headers. This also means that all places that don't care about the differences can just check O_DSYNC and get the right behaviour for O_SYNC, too - only places that actuall care need to check __O_SYNC in addition. Drivers and network filesystems have been updated in a fail safe way to always do the full sync magic if O_DSYNC is set. The few places setting O_SYNC for lower layers are kept that way for now to stay failsafe. We enforce that O_DSYNC is set when __O_SYNC is set early in the open path to make sure we always get these sane options. Note that parisc really screwed up their headers as they already define a O_DSYNC that has always been a no-op. We try to repair it by using it for the new O_DSYNC and redefinining O_SYNC to send both the traditional O_SYNC numerical value _and_ the O_DSYNC one. Cc: Richard Henderson Cc: Ivan Kokshaysky Cc: Grant Grundler Cc: "David S. Miller" Cc: Ingo Molnar Cc: "H. Peter Anvin" Cc: Thomas Gleixner Cc: Al Viro Cc: Andreas Dilger Acked-by: Trond Myklebust Acked-by: Kyle McMartin Acked-by: Ulrich Drepper Signed-off-by: Christoph Hellwig Signed-off-by: Andrew Morton Signed-off-by: Jan Kara

writeback: get rid of wbc->for_writepages

2009-09-16T13:16:18Z

It's only set, it's never checked. Kill it. Acked-by: Jan Kara Signed-off-by: Jens Axboe