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2013-07-02Merge tag 'ext4_for_linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4 Pull ext4 update from Ted Ts'o: "Lots of bug fixes, cleanups and optimizations. In the bug fixes category, of note is a fix for on-line resizing file systems where the block size is smaller than the page size (i.e., file systems 1k blocks on x86, or more interestingly file systems with 4k blocks on Power or ia64 systems.) In the cleanup category, the ext4's punch hole implementation was significantly improved by Lukas Czerner, and now supports bigalloc file systems. In addition, Jan Kara significantly cleaned up the write submission code path. We also improved error checking and added a few sanity checks. In the optimizations category, two major optimizations deserve mention. The first is that ext4_writepages() is now used for nodelalloc and ext3 compatibility mode. This allows writes to be submitted much more efficiently as a single bio request, instead of being sent as individual 4k writes into the block layer (which then relied on the elevator code to coalesce the requests in the block queue). Secondly, the extent cache shrink mechanism, which was introduce in 3.9, no longer has a scalability bottleneck caused by the i_es_lru spinlock. Other optimizations include some changes to reduce CPU usage and to avoid issuing empty commits unnecessarily." * tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (86 commits) ext4: optimize starting extent in ext4_ext_rm_leaf() jbd2: invalidate handle if jbd2_journal_restart() fails ext4: translate flag bits to strings in tracepoints ext4: fix up error handling for mpage_map_and_submit_extent() jbd2: fix theoretical race in jbd2__journal_restart ext4: only zero partial blocks in ext4_zero_partial_blocks() ext4: check error return from ext4_write_inline_data_end() ext4: delete unnecessary C statements ext3,ext4: don't mess with dir_file->f_pos in htree_dirblock_to_tree() jbd2: move superblock checksum calculation to jbd2_write_superblock() ext4: pass inode pointer instead of file pointer to punch hole ext4: improve free space calculation for inline_data ext4: reduce object size when !CONFIG_PRINTK ext4: improve extent cache shrink mechanism to avoid to burn CPU time ext4: implement error handling of ext4_mb_new_preallocation() ext4: fix corruption when online resizing a fs with 1K block size ext4: delete unused variables ext4: return FIEMAP_EXTENT_UNKNOWN for delalloc extents jbd2: remove debug dependency on debug_fs and update Kconfig help text jbd2: use a single printk for jbd_debug() ...
2013-07-01ext4: pass inode pointer instead of file pointer to punch holeAshish Sangwan
No need to pass file pointer when we can directly pass inode pointer. Signed-off-by: Ashish Sangwan <a.sangwan@samsung.com> Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2013-07-01ext4: reduce object size when !CONFIG_PRINTKJoe Perches
Reduce the object size ~10% could be useful for embedded systems. Add #ifdef CONFIG_PRINTK #else #endif blocks to hold formats and arguments, passing " " to functions when !CONFIG_PRINTK and still verifying format and arguments with no_printk. $ size fs/ext4/built-in.o* text data bss dec hex filename 239375 610 888 240873 3ace9 fs/ext4/built-in.o.new 264167 738 888 265793 40e41 fs/ext4/built-in.o.old $ grep -E "CONFIG_EXT4|CONFIG_PRINTK" .config # CONFIG_PRINTK is not set CONFIG_EXT4_FS=y CONFIG_EXT4_USE_FOR_EXT23=y CONFIG_EXT4_FS_POSIX_ACL=y # CONFIG_EXT4_FS_SECURITY is not set # CONFIG_EXT4_DEBUG is not set Signed-off-by: Joe Perches <joe@perches.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2013-07-01ext4: improve extent cache shrink mechanism to avoid to burn CPU timeZheng Liu
Now we maintain an proper in-order LRU list in ext4 to reclaim entries from extent status tree when we are under heavy memory pressure. For keeping this order, a spin lock is used to protect this list. But this lock burns a lot of CPU time. We can use the following steps to trigger it. % cd /dev/shm % dd if=/dev/zero of=ext4-img bs=1M count=2k % mkfs.ext4 ext4-img % mount -t ext4 -o loop ext4-img /mnt % cd /mnt % for ((i=0;i<160;i++)); do truncate -s 64g $i; done % for ((i=0;i<160;i++)); do cp $i /dev/null &; done % perf record -a -g % perf report This commit tries to fix this problem. Now a new member called i_touch_when is added into ext4_inode_info to record the last access time for an inode. Meanwhile we never need to keep a proper in-order LRU list. So this can avoid to burns some CPU time. When we try to reclaim some entries from extent status tree, we use list_sort() to get a proper in-order list. Then we traverse this list to discard some entries. In ext4_sb_info, we use s_es_last_sorted to record the last time of sorting this list. When we traverse the list, we skip the inode that is newer than this time, and move this inode to the tail of LRU list. When the head of the list is newer than s_es_last_sorted, we will sort the LRU list again. In this commit, we break the loop if s_extent_cache_cnt == 0 because that means that all extents in extent status tree have been reclaimed. Meanwhile in this commit, ext4_es_{un}register_shrinker()'s prototype is changed to save a local variable in these functions. Reported-by: Dave Hansen <dave.hansen@intel.com> Signed-off-by: Zheng Liu <wenqing.lz@taobao.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2013-06-29[readdir] convert ext4Al Viro
and trim the living hell out bogosities in inline dir case Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2013-06-06ext4: add sanity check to ext4_get_group_info()Theodore Ts'o
The group number passed to ext4_get_group_info() should be valid, but let's add an assert to check this before we start creating a pointer based on that group number and dereferencing it. Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2013-06-04ext4: remove ext4_ioend_wait()Jan Kara
Now that we clear PageWriteback after extent conversion, there's no need to wait for io_end processing in ext4_evict_inode(). Running AIO/DIO keeps file reference until aio_complete() is called so ext4_evict_inode() cannot be called. For io_end structures resulting from buffered IO waiting is happening because we wait for PageWriteback in truncate_inode_pages(). Reviewed-by: Zheng Liu <wenqing.lz@taobao.com> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2013-06-04ext4: don't wait for extent conversion in ext4_punch_hole()Jan Kara
We don't have to wait for extent conversion in ext4_punch_hole() as buffered IO for the punched range has been flushed and waited upon (thus all extent conversions for that range have completed). Also we wait for all DIO to finish using inode_dio_wait() so there cannot be any extent conversions pending due to direct IO. Also remove ext4_flush_unwritten_io() since it's unused now. Reviewed-by: Zheng Liu <wenqing.lz@taobao.com> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2013-06-04ext4: defer clearing of PageWriteback after extent conversionJan Kara
Currently PageWriteback bit gets cleared from put_io_page() called from ext4_end_bio(). This is somewhat inconvenient as extent tree is not fully updated at that time (unwritten extents are not marked as written) so we cannot read the data back yet. This design was dictated by lock ordering as we cannot start a transaction while PageWriteback bit is set (we could easily deadlock with ext4_da_writepages()). But now that we use transaction reservation for extent conversion, locking issues are solved and we can move PageWriteback bit clearing after extent conversion is done. As a result we can remove wait for unwritten extent conversion from ext4_sync_file() because it already implicitely happens through wait_on_page_writeback(). We implement deferring of PageWriteback clearing by queueing completed bios to appropriate io_end and processing all the pages when io_end is going to be freed instead of at the moment ext4_io_end() is called. Reviewed-by: Zheng Liu <wenqing.lz@taobao.com> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2013-06-04ext4: split extent conversion lists to reserved & unreserved partsJan Kara
Now that we have extent conversions with reserved transaction, we have to prevent extent conversions without reserved transaction (from DIO code) to block these (as that would effectively void any transaction reservation we did). So split lists, work items, and work queues to reserved and unreserved parts. Reviewed-by: Zheng Liu <wenqing.lz@taobao.com> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2013-06-04ext4: use transaction reservation for extent conversion in ext4_end_ioJan Kara
Later we would like to clear PageWriteback bit only after extent conversion from unwritten to written extents is performed. However it is not possible to start a transaction after PageWriteback is set because that violates lock ordering (and is easy to deadlock). So we have to reserve a transaction before locking pages and sending them for IO and later we use the transaction for extent conversion from ext4_end_io(). Reviewed-by: Zheng Liu <wenqing.lz@taobao.com> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2013-06-04ext4: remove buffer_uninit handlingJan Kara
There isn't any need for setting BH_Uninit on buffers anymore. It was only used to signal we need to mark io_end as needing extent conversion in add_bh_to_extent() but now we can mark the io_end directly when mapping extent. Reviewed-by: Zheng Liu <wenqing.lz@taobao.com> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2013-06-04ext4: restructure writeback pathJan Kara
There are two issues with current writeback path in ext4. For one we don't necessarily map complete pages when blocksize < pagesize and thus needn't do any writeback in one iteration. We always map some blocks though so we will eventually finish mapping the page. Just if writeback races with other operations on the file, forward progress is not really guaranteed. The second problem is that current code structure makes it hard to associate all the bios to some range of pages with one io_end structure so that unwritten extents can be converted after all the bios are finished. This will be especially difficult later when io_end will be associated with reserved transaction handle. We restructure the writeback path to a relatively simple loop which first prepares extent of pages, then maps one or more extents so that no page is partially mapped, and once page is fully mapped it is submitted for IO. We keep all the mapping and IO submission information in mpage_da_data structure to somewhat reduce stack usage. Resulting code is somewhat shorter than the old one and hopefully also easier to read. Reviewed-by: Zheng Liu <wenqing.lz@taobao.com> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2013-06-04ext4: better estimate credits needed for ext4_da_writepages()Jan Kara
We limit the number of blocks written in a single loop of ext4_da_writepages() to 64 when inode uses indirect blocks. That is unnecessary as credit estimates for mapping logically continguous run of blocks is rather low even for inode with indirect blocks. So just lift this limitation and properly calculate the number of necessary credits. This better credit estimate will also later allow us to always write at least a single page in one iteration. Reviewed-by: Zheng Liu <wenqing.lz@taobao.com> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2013-06-04ext4: improve writepage credit estimate for files with indirect blocksJan Kara
ext4_ind_trans_blocks() wrongly used 'chunk' argument to decide whether blocks mapped are logically contiguous. That is wrong since the argument informs whether the blocks are physically contiguous. As the blocks mapped are always logically contiguous and that's all ext4_ind_trans_blocks() cares about, just remove the 'chunk' argument. Reviewed-by: Zheng Liu <wenqing.lz@taobao.com> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2013-06-04ext4: deprecate max_writeback_mb_bump sysfs attributeJan Kara
This attribute is now unused so deprecate it. We still show the old default value to keep some compatibility but we don't allow writing to that attribute anymore. Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2013-06-04ext4: use io_end for multiple biosJan Kara
Change writeback path to create just one io_end structure for the extent to which we submit IO and share it among bios writing that extent. This prevents needless splitting and joining of unwritten extents when they cannot be submitted as a single bio. Bugs in ENOMEM handling found by Linux File System Verification project (linuxtesting.org) and fixed by Alexey Khoroshilov <khoroshilov@ispras.ru>. CC: Alexey Khoroshilov <khoroshilov@ispras.ru> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2013-05-28ext4: remove unused discard_partial_page_buffersLukas Czerner
The discard_partial_page_buffers is no longer used anywhere so we can simply remove it including the *_no_lock variant and EXT4_DISCARD_PARTIAL_PG_ZERO_UNMAPPED define. Signed-off-by: Lukas Czerner <lczerner@redhat.com> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2013-05-28ext4: use ext4_zero_partial_blocks in punch_holeLukas Czerner
We're doing to get rid of ext4_discard_partial_page_buffers() since it is duplicating some code and also partially duplicating work of truncate_pagecache_range(), moreover the old implementation was much clearer. Now when the truncate_inode_pages_range() can handle truncating non page aligned regions we can use this to invalidate and zero out block aligned region of the punched out range and then use ext4_block_truncate_page() to zero the unaligned blocks on the start and end of the range. This will greatly simplify the punch hole code. Moreover after this commit we can get rid of the ext4_discard_partial_page_buffers() completely. We also introduce function ext4_prepare_punch_hole() to do come common operations before we attempt to do the actual punch hole on indirect or extent file which saves us some code duplication. This has been tested on ppc64 with 1k block size with fsx and xfstests without any problems. Signed-off-by: Lukas Czerner <lczerner@redhat.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2013-05-28Revert "ext4: remove no longer used functions in inode.c"Lukas Czerner
This reverts commit ccb4d7af914e0fe9b2f1022f8ea6c300463fd5e6. This commit reintroduces functions ext4_block_truncate_page() and ext4_block_zero_page_range() which has been previously removed in favour of ext4_discard_partial_page_buffers(). In future commits we want to reintroduce those function and remove ext4_discard_partial_page_buffers() since it is duplicating some code and also partially duplicating work of truncate_pagecache_range(), moreover the old implementation was much clearer. Signed-off-by: Lukas Czerner <lczerner@redhat.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2013-05-11ext4: revert "ext4: use io_end for multiple bios"Theodore Ts'o
This reverts commit 4eec708d263f0ee10861d69251708a225b64cac7. Multiple users have reported crashes which is apparently caused by this commit. Thanks to Dmitry Monakhov for bisecting it. Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Cc: Dmitry Monakhov <dmonakhov@openvz.org> Cc: Jan Kara <jack@suse.cz>
2013-04-19ext4: fix readdir error in the case of inline_data+dir_indexTao Ma
Zach reported a problem that if inline data is enabled, we don't tell the difference between the offset of '.' and '..'. And a getdents will fail if the user only want to get '.' and what's worse, if there is a conversion happens when the user calls getdents many times, he/she may get the same entry twice. In theory, a dir block would also fail if it is converted to a hashed-index based dir since f_pos will become a hash value, not the real one, but it doesn't happen. And a deep investigation shows that we uses a hash based solution even for a normal dir if the dir_index feature is enabled. So this patch just adds a new htree_inlinedir_to_tree for inline dir, and if we find that the hash index is supported, we will do like what we do for a dir block. Reported-by: Zach Brown <zab@redhat.com> Signed-off-by: Tao Ma <boyu.mt@taobao.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2013-04-12ext4: use io_end for multiple biosJan Kara
Change writeback path to create just one io_end structure for the extent to which we submit IO and share it among bios writing that extent. This prevents needless splitting and joining of unwritten extents when they cannot be submitted as a single bio. Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Reviewed-by: Dmitry Monakhov <dmonakhov@openvz.org> Reviewed-by: Zheng Liu <wenqing.lz@taobao.com>
2013-04-12ext4: make ext4_bio_write_page() use BH_Async_Write flagsJan Kara
So far ext4_bio_write_page() attached all the pages to ext4_io_end structure. This makes that structure pretty heavy (1 KB for pointers + 16 bytes per page attached to the bio). Also later we would like to share ext4_io_end structure among several bios in case IO to a single extent needs to be split among several bios and pointing to pages from ext4_io_end makes this complex. We remove page pointers from ext4_io_end and use pointers from bio itself instead. This isn't as easy when blocksize < pagesize because then we can have several bios in flight for a single page and we have to be careful when to call end_page_writeback(). However this is a known problem already solved by block_write_full_page() / end_buffer_async_write() so we mimic its behavior here. We mark buffers going to disk with BH_Async_Write flag and in ext4_bio_end_io() we check whether there are any buffers with BH_Async_Write flag left. If there are not, we can call end_page_writeback(). Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Reviewed-by: Dmitry Monakhov <dmonakhov@openvz.org> Reviewed-by: Zheng Liu <wenqing.lz@taobao.com>
2013-04-11ext4: move ext4_ind_migrate() into migrate.cLukas Czerner
Move ext4_ind_migrate() into migrate.c file since it makes much more sense and ext4_ext_migrate() is there as well. Also fix tiny style problem - add spaces around "=" in "i=0". Signed-off-by: Lukas Czerner <lczerner@redhat.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2013-04-10ext4: introduce reserved spaceLukas Czerner
Currently in ENOSPC condition when writing into unwritten space, or punching a hole, we might need to split the extent and grow extent tree. However since we can not allocate any new metadata blocks we'll have to zero out unwritten part of extent or punched out part of extent, or in the worst case return ENOSPC even though use actually does not allocate any space. Also in delalloc path we do reserve metadata and data blocks for the time we're going to write out, however metadata block reservation is very tricky especially since we expect that logical connectivity implies physical connectivity, however that might not be the case and hence we might end up allocating more metadata blocks than previously reserved. So in future, metadata reservation checks should be removed since we can not assure that we do not under reserve. And this is where reserved space comes into the picture. When mounting the file system we slice off a little bit of the file system space (2% or 4096 clusters, whichever is smaller) which can be then used for the cases mentioned above to prevent costly zeroout, or unexpected ENOSPC. The number of reserved clusters can be set via sysfs, however it can never be bigger than number of free clusters in the file system. Note that this patch fixes the failure of xfstest 274 as expected. Signed-off-by: Lukas Czerner <lczerner@redhat.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
2013-04-08ext4: implementation of a new ioctl called EXT4_IOC_SWAP_BOOTDr. Tilmann Bubeck
Add a new ioctl, EXT4_IOC_SWAP_BOOT which swaps i_blocks and associated attributes (like i_blocks, i_size, i_flags, ...) from the specified inode with inode EXT4_BOOT_LOADER_INO (#5). This is typically used to store a boot loader in a secure part of the filesystem, where it can't be changed by a normal user by accident. The data blocks of the previous boot loader will be associated with the given inode. This usercode program is a simple example of the usage: int main(int argc, char *argv[]) { int fd; int err; if ( argc != 2 ) { printf("usage: ext4-swap-boot-inode FILE-TO-SWAP\n"); exit(1); } fd = open(argv[1], O_WRONLY); if ( fd < 0 ) { perror("open"); exit(1); } err = ioctl(fd, EXT4_IOC_SWAP_BOOT); if ( err < 0 ) { perror("ioctl"); exit(1); } close(fd); exit(0); } [ Modified by Theodore Ts'o to fix a number of bugs in the original code.] Signed-off-by: Dr. Tilmann Bubeck <t.bubeck@reinform.de> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2013-04-04ext4: introduce ext4_get_group_number()Lukas Czerner
Currently on many places in ext4 we're using ext4_get_group_no_and_offset() even though we're only interested in knowing the block group of the particular block, not the offset within the block group so we can use more efficient way to compute block group. This patch introduces ext4_get_group_number() which computes block group for a given block much more efficiently. Use this function instead of ext4_get_group_no_and_offset() everywhere where we're only interested in knowing the block group. Signed-off-by: Lukas Czerner <lczerner@redhat.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2013-04-04ext4: make ext4_block_in_group() much more efficientLukas Czerner
Currently in when getting the block group number for a particular block in ext4_block_in_group() we're using ext4_get_group_no_and_offset() which uses do_div() to get the block group and the remainer which is offset within the group. We don't need all of that in ext4_block_in_group() as we only need to figure out the group number. This commit changes ext4_block_in_group() to calculate group number directly. This shows as a big improvement with regards to cpu utilization. Measuring fallocate -l 15T on fresh file system with perf showed that 23% of cpu time was spend in the ext4_get_group_no_and_offset(). With this change it completely disappears from the list only bumping the occurrence of ext4_init_block_bitmap() which is the biggest user of ext4_block_in_group() by 4%. As the result of this change on my system the fallocate call was approx. 10% faster. However since there is '-g' option in mkfs which allow us setting different groups size (mostly for developers) I've introduced new per file system flag whether we have a standard block group size or not. The flag is used to determine whether we can use the bit shift optimization or not. Signed-off-by: Lukas Czerner <lczerner@redhat.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2013-04-04ext4: support simple conversion of extent-mapped inodes to use i_blocksTheodore Ts'o
In order to make it simpler to test the code which support i_blocks/indirect-mapped inodes, support the conversion of inodes which are less than 12 blocks and which are contained in no more than a single extent. The primary intended use of this code is to converting freshly created zero-length files and empty directories. Note that the version of chattr in e2fsprogs 1.42.7 and earlier has a check that prevents the clearing of the extent flag. A simple patch which allows "chattr -e <file>" to work will be checked into the e2fsprogs git repository. Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2013-04-03ext4: refactor truncate codeTheodore Ts'o
Move common code in ext4_ind_truncate() and ext4_ext_truncate() into ext4_truncate(). This saves over 60 lines of code. Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2013-04-03ext4: refactor punch hole codeTheodore Ts'o
Move common code in ext4_ind_punch_hole() and ext4_ext_punch_hole() into ext4_punch_hole(). This saves over 150 lines of code. This also fixes a potential bug when the punch_hole() code is racing against indirect-to-extents or extents-to-indirect migation. We are currently using i_mutex to protect against changes to the inode flag; specifically, the append-only, immutable, and extents inode flags. So we need to take i_mutex before deciding whether to use the extents-specific or indirect-specific punch_hole code. Also, there was a missing call to ext4_inode_block_unlocked_dio() in the indirect punch codepath. This was added in commit 02d262dffcf4c to block DIO readers racing against the punch operation in the codepath for extent-mapped inodes, but it was missing for indirect-block mapped inodes. One of the advantages of refactoring the code is that it makes such oversights much less likely. Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2013-04-03ext4: collapse handling of data=ordered and data=writeback codepathsTheodore Ts'o
The only difference between how we handle data=ordered and data=writeback is a single call to ext4_jbd2_file_inode(). Eliminate code duplication by factoring out redundant the code paths. Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Reviewed-by: Lukas Czerner <lczerner@redhat.com>
2013-03-20ext4: fix ext4_evict_inode() racing against workqueue processing codeTheodore Ts'o
Commit 84c17543ab56 (ext4: move work from io_end to inode) triggered a regression when running xfstest #270 when the file system is mounted with dioread_nolock. The problem is that after ext4_evict_inode() calls ext4_ioend_wait(), this guarantees that last io_end structure has been freed, but it does not guarantee that the workqueue structure, which was moved into the inode by commit 84c17543ab56, is actually finished. Once ext4_flush_completed_IO() calls ext4_free_io_end() on CPU #1, this will allow ext4_ioend_wait() to return on CPU #2, at which point the evict_inode() codepath can race against the workqueue code on CPU #1 accessing EXT4_I(inode)->i_unwritten_work to find the next item of work to do. Fix this by calling cancel_work_sync() in ext4_ioend_wait(), which will be renamed ext4_ioend_shutdown(), since it is only used by ext4_evict_inode(). Also, move the call to ext4_ioend_shutdown() until after truncate_inode_pages() and filemap_write_and_wait() are called, to make sure all dirty pages have been written back and flushed from the page cache first. BUG: unable to handle kernel NULL pointer dereference at (null) IP: [<c01dda6a>] cwq_activate_delayed_work+0x3b/0x7e *pdpt = 0000000030bc3001 *pde = 0000000000000000 Oops: 0000 [#1] SMP DEBUG_PAGEALLOC Modules linked in: Pid: 6, comm: kworker/u:0 Not tainted 3.8.0-rc3-00013-g84c1754-dirty #91 Bochs Bochs EIP: 0060:[<c01dda6a>] EFLAGS: 00010046 CPU: 0 EIP is at cwq_activate_delayed_work+0x3b/0x7e EAX: 00000000 EBX: 00000000 ECX: f505fe54 EDX: 00000000 ESI: ed5b697c EDI: 00000006 EBP: f64b7e8c ESP: f64b7e84 DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0068 CR0: 8005003b CR2: 00000000 CR3: 30bc2000 CR4: 000006f0 DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000 DR6: ffff0ff0 DR7: 00000400 Process kworker/u:0 (pid: 6, ti=f64b6000 task=f64b4160 task.ti=f64b6000) Stack: f505fe00 00000006 f64b7e9c c01de3d7 f6435540 00000003 f64b7efc c01def1d f6435540 00000002 00000000 0000008a c16d0808 c040a10b c16d07d8 c16d08b0 f505fe00 c16d0780 00000000 00000000 ee153df4 c1ce4a30 c17d0e30 00000000 Call Trace: [<c01de3d7>] cwq_dec_nr_in_flight+0x71/0xfb [<c01def1d>] process_one_work+0x5d8/0x637 [<c040a10b>] ? ext4_end_bio+0x300/0x300 [<c01e3105>] worker_thread+0x249/0x3ef [<c01ea317>] kthread+0xd8/0xeb [<c01e2ebc>] ? manage_workers+0x4bb/0x4bb [<c023a370>] ? trace_hardirqs_on+0x27/0x37 [<c0f1b4b7>] ret_from_kernel_thread+0x1b/0x28 [<c01ea23f>] ? __init_kthread_worker+0x71/0x71 Code: 01 83 15 ac ff 6c c1 00 31 db 89 c6 8b 00 a8 04 74 12 89 c3 30 db 83 05 b0 ff 6c c1 01 83 15 b4 ff 6c c1 00 89 f0 e8 42 ff ff ff <8b> 13 89 f0 83 05 b8 ff 6c c1 6c c1 00 31 c9 83 EIP: [<c01dda6a>] cwq_activate_delayed_work+0x3b/0x7e SS:ESP 0068:f64b7e84 CR2: 0000000000000000 ---[ end trace a1923229da53d8a4 ]--- Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Cc: Jan Kara <jack@suse.cz>
2013-03-12ext4: use atomic64_t for the per-flexbg free_clusters countTheodore Ts'o
A user who was using a 8TB+ file system and with a very large flexbg size (> 65536) could cause the atomic_t used in the struct flex_groups to overflow. This was detected by PaX security patchset: http://forums.grsecurity.net/viewtopic.php?f=3&t=3289&p=12551#p12551 This bug was introduced in commit 9f24e4208f7e, so it's been around since 2.6.30. :-( Fix this by using an atomic64_t for struct orlav_stats's free_clusters. Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Reviewed-by: Lukas Czerner <lczerner@redhat.com> Cc: stable@vger.kernel.org
2013-03-02ext4: use percpu counter for extent cache countTheodore Ts'o
Use a percpu counter rather than atomic types for shrinker accounting. There's no need for ultimate accuracy in the shrinker, so this should come a little more cheaply. The percpu struct is somewhat large, but there was a big gap before the cache-aligned s_es_lru_lock anyway, and it fits nicely in there. Signed-off-by: Eric Sandeen <sandeen@redhat.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2013-03-01ext4: optimize ext4_es_shrink()Theodore Ts'o
When the system is under memory pressure, ext4_es_srhink() will get called very often. So optimize returning the number of items in the file system's extent status cache by keeping a per-filesystem count, instead of calculating it each time by scanning all of the inodes in the extent status cache. Also rename the slab used for the extent status cache to be "ext4_extent_status" so it's obviousl the slab in question is created by ext4. Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Cc: Zheng Liu <gnehzuil.liu@gmail.com>
2013-02-18ext4: reclaim extents from extent status treeZheng Liu
Although extent status is loaded on-demand, we also need to reclaim extent from the tree when we are under a heavy memory pressure because in some cases fragmented extent tree causes status tree costs too much memory. Here we maintain a lru list in super_block. When the extent status of an inode is accessed and changed, this inode will be move to the tail of the list. The inode will be dropped from this list when it is cleared. In the inode, a counter is added to count the number of cached objects in extent status tree. Here only written/unwritten/hole extent is counted because delayed extent doesn't be reclaimed due to fiemap, bigalloc and seek_data/hole need it. The counter will be increased as a new extent is allocated, and it will be decreased as a extent is freed. In this commit we use normal shrinker framework to reclaim memory from the status tree. ext4_es_reclaim_extents_count() traverses the lru list to count the number of reclaimable extents. ext4_es_shrink() tries to reclaim written/unwritten/hole extents from extent status tree. The inode that has been shrunk is moved to the tail of lru list. Signed-off-by: Zheng Liu <wenqing.lz@taobao.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Cc: Jan kara <jack@suse.cz>
2013-02-18ext4: remove single extent cacheZheng Liu
Single extent cache could be removed because we have extent status tree as a extent cache, and it would be better. Signed-off-by: Zheng Liu <wenqing.lz@taobao.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Cc: Jan kara <jack@suse.cz>
2013-02-18ext4: lookup block mapping in extent status treeZheng Liu
After tracking all extent status, we already have a extent cache in memory. Every time we want to lookup a block mapping, we can first try to lookup it in extent status tree to avoid a potential disk I/O. A new function called ext4_es_lookup_extent is defined to finish this work. When we try to lookup a block mapping, we always call ext4_map_blocks and/or ext4_da_map_blocks. So in these functions we first try to lookup a block mapping in extent status tree. A new flag EXT4_GET_BLOCKS_NO_PUT_HOLE is used in ext4_da_map_blocks in order not to put a hole into extent status tree because this hole will be converted to delayed extent in the tree immediately. Signed-off-by: Zheng Liu <wenqing.lz@taobao.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Cc: Jan kara <jack@suse.cz>
2013-02-18ext4: track all extent status in extent status treeZheng Liu
By recording the phycisal block and status, extent status tree is able to track the status of every extents. When we call _map_blocks functions to lookup an extent or create a new written/unwritten/delayed extent, this extent will be inserted into extent status tree. We don't load all extents from disk in alloc_inode() because it costs too much memory, and if a file is opened and closed frequently it will takes too much time to load all extent information. So currently when we create/lookup an extent, this extent will be inserted into extent status tree. Hence, the extent status tree may not comprehensively contain all of the extents found in the file. Here a condition we need to take care is that an extent might contains unwritten and delayed status simultaneously because an extent is delayed allocated and could be allocated by fallocate. At this time we need to keep delayed status because later we need to update delayed reservation space using it. Signed-off-by: Zheng Liu <wenqing.lz@taobao.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Cc: Jan kara <jack@suse.cz>
2013-02-09ext4: start handle at the last possible moment when creating inodesTheodore Ts'o
In ext4_{create,mknod,mkdir,symlink}(), don't start the journal handle until the inode has been succesfully allocated. In order to do this, we need to start the handle in the ext4_new_inode(). So create a new variant of this function, ext4_new_inode_start_handle(), so the handle can be created at the last possible minute, before we need to modify the inode allocation bitmap block. Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2013-02-09ext4: fix the number of credits needed for acl ops with inline dataTheodore Ts'o
Operations which modify extended attributes may need extra journal credits if inline data is used, since there is a chance that some extended attributes may need to get pushed to an external attribute block. Changes to reflect this was made in xattr.c, but they were missed in fs/ext4/acl.c. To fix this, abstract the calculation of the number of credits needed for xattr operations to an inline function defined in ext4_jbd2.h, and use it in acl.c and xattr.c. Also move the function declarations used in inline.c from xattr.h (where they are non-obviously hidden, and caused problems since ext4_jbd2.h needs to use the function ext4_has_inline_data), and move them to ext4.h. Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Reviewed-by: Tao Ma <boyu.mt@taobao.com> Reviewed-by: Jan Kara <jack@suse.cz>
2013-02-08ext4: move the jbd2 wrapper functions out of super.cTheodore Ts'o
Move the jbd2 wrapper functions which start and stop handles out of super.c, where they don't really logically belong, and into ext4_jbd2.c. Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2013-01-28ext4: move work from io_end to inodeJan Kara
It does not make much sense to have struct work in ext4_io_end_t because we always use it for only one ext4_io_end_t per inode (the first one in the i_completed_io list). So just move the structure to inode itself. This also allows for a small simplification in processing io_end structures. Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2013-01-28ext4: Always use ext4_bio_write_page() for writeoutJan Kara
Currently we sometimes used block_write_full_page() and sometimes ext4_bio_write_page() for writeback (depending on mount options and call path). Let's always use ext4_bio_write_page() to simplify things a bit. Reviewed-by: Zheng Liu <wenqing.lz@taobao.com> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2013-01-28ext4: add punching hole support for non-extent-mapped filesZheng Liu
This patch add supports for indirect file support punching hole. It is almost the same as ext4_ext_punch_hole. First, we invalidate all pages between this hole, and then we try to deallocate all blocks of this hole. A recursive function is used to handle deallocation of blocks. In this function, it iterates over the entries in inode's i_blocks or indirect blocks, and try to free the block for each one of them. After applying this patch, xfstest #255 will not pass w/o extent because indirect-based file doesn't support unwritten extents. Signed-off-by: Zheng Liu <wenqing.lz@taobao.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2013-01-13ext4: trigger the lazy inode table initialization after resizeTheodore Ts'o
After we have finished extending the file system, we need to trigger a the lazy inode table thread to zero out the inode tables. Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2012-12-17Merge tag 'ext4_for_linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4 Pull ext4 update from Ted Ts'o: "There are two major features for this merge window. The first is inline data, which allows small files or directories to be stored in the in-inode extended attribute area. (This requires that the file system use inodes which are at least 256 bytes or larger; 128 byte inodes do not have any room for in-inode xattrs.) The second new feature is SEEK_HOLE/SEEK_DATA support. This is enabled by the extent status tree patches, and this infrastructure will be used to further optimize ext4 in the future. Beyond that, we have the usual collection of code cleanups and bug fixes." * tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (63 commits) ext4: zero out inline data using memset() instead of empty_zero_page ext4: ensure Inode flags consistency are checked at build time ext4: Remove CONFIG_EXT4_FS_XATTR ext4: remove unused variable from ext4_ext_in_cache() ext4: remove redundant initialization in ext4_fill_super() ext4: remove redundant code in ext4_alloc_inode() ext4: use sync_inode_metadata() when syncing inode metadata ext4: enable ext4 inline support ext4: let fallocate handle inline data correctly ext4: let ext4_truncate handle inline data correctly ext4: evict inline data out if we need to strore xattr in inode ext4: let fiemap work with inline data ext4: let ext4_rename handle inline dir ext4: let empty_dir handle inline dir ext4: let ext4_delete_entry() handle inline data ext4: make ext4_delete_entry generic ext4: let ext4_find_entry handle inline data ext4: create a new function search_dir ext4: let ext4_readdir handle inline data ext4: let add_dir_entry handle inline data properly ...
2012-12-10ext4: ensure Inode flags consistency are checked at build timeCarlos Maiolino
Flags being used by atomic operations in inode flags (e.g. ext4_test_inode_flag(), should be consistent with that actually stored in inodes, i.e.: EXT4_XXX_FL. It ensures that this consistency is checked at build-time, not at run-time. Currently, the flags consistency are being checked at run-time, but, there is no real reason to not do a build-time check instead of a run-time check. The code is comparing macro defined values with enum type variables, where both are constants, so, there is no problem in comparing constants at build-time. enum variables are treated as constants by the C compiler, according to the C99 specs (see www.open-std.org/jtc1/sc22/wg14/www/docs/n1124.pdf sec. 6.2.5, item 16), so, there is no real problem in comparing an enumeration type at build time Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>