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2020-06-25ext4: fix partial cluster initialization when splitting extentSasha Levin
[ Upstream commit cfb3c85a600c6aa25a2581b3c1c4db3460f14e46 ] Fix the bug when calculating the physical block number of the first block in the split extent. This bug will cause xfstests shared/298 failure on ext4 with bigalloc enabled occasionally. Ext4 error messages indicate that previously freed blocks are being freed again, and the following fsck will fail due to the inconsistency of block bitmap and bg descriptor. The following is an example case: 1. First, Initialize a ext4 filesystem with cluster size '16K', block size '4K', in which case, one cluster contains four blocks. 2. Create one file (e.g., xxx.img) on this ext4 filesystem. Now the extent tree of this file is like: ... 36864:[0]4:220160 36868:[0]14332:145408 51200:[0]2:231424 ... 3. Then execute PUNCH_HOLE fallocate on this file. The hole range is like: .. ext4_ext_remove_space: dev 254,16 ino 12 since 49506 end 49506 depth 1 ext4_ext_remove_space: dev 254,16 ino 12 since 49544 end 49546 depth 1 ext4_ext_remove_space: dev 254,16 ino 12 since 49605 end 49607 depth 1 ... 4. Then the extent tree of this file after punching is like ... 49507:[0]37:158047 49547:[0]58:158087 ... 5. Detailed procedure of punching hole [49544, 49546] 5.1. The block address space: ``` lblk ~49505 49506 49507~49543 49544~49546 49547~ ---------+------+-------------+----------------+-------- extent | hole | extent | hole | extent ---------+------+-------------+----------------+-------- pblk ~158045 158046 158047~158083 158084~158086 158087~ ``` 5.2. The detailed layout of cluster 39521: ``` cluster 39521 <-------------------------------> hole extent <----------------------><-------- lblk 49544 49545 49546 49547 +-------+-------+-------+-------+ | | | | | +-------+-------+-------+-------+ pblk 158084 1580845 158086 158087 ``` 5.3. The ftrace output when punching hole [49544, 49546]: - ext4_ext_remove_space (start 49544, end 49546) - ext4_ext_rm_leaf (start 49544, end 49546, last_extent [49507(158047), 40], partial [pclu 39522 lblk 0 state 2]) - ext4_remove_blocks (extent [49507(158047), 40], from 49544 to 49546, partial [pclu 39522 lblk 0 state 2] - ext4_free_blocks: (block 158084 count 4) - ext4_mballoc_free (extent 1/6753/1) 5.4. Ext4 error message in dmesg: EXT4-fs error (device vdb): mb_free_blocks:1457: group 1, block 158084:freeing already freed block (bit 6753); block bitmap corrupt. EXT4-fs error (device vdb): ext4_mb_generate_buddy:747: group 1, block bitmap and bg descriptor inconsistent: 19550 vs 19551 free clusters In this case, the whole cluster 39521 is freed mistakenly when freeing pblock 158084~158086 (i.e., the first three blocks of this cluster), although pblock 158087 (the last remaining block of this cluster) has not been freed yet. The root cause of this isuue is that, the pclu of the partial cluster is calculated mistakenly in ext4_ext_remove_space(). The correct partial_cluster.pclu (i.e., the cluster number of the first block in the next extent, that is, lblock 49597 (pblock 158086)) should be 39521 rather than 39522. Fixes: f4226d9ea400 ("ext4: fix partial cluster initialization") Signed-off-by: Jeffle Xu <jefflexu@linux.alibaba.com> Reviewed-by: Eric Whitney <enwlinux@gmail.com> Cc: stable@kernel.org # v3.19+ Link: https://lore.kernel.org/r/1590121124-37096-1-git-send-email-jefflexu@linux.alibaba.com Signed-off-by: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-04-29ext4: fix extent_status fragmentation for plain filesDmitry Monakhov
[ Upstream commit 4068664e3cd2312610ceac05b74c4cf1853b8325 ] Extents are cached in read_extent_tree_block(); as a result, extents are not cached for inodes with depth == 0 when we try to find the extent using ext4_find_extent(). The result of the lookup is cached in ext4_map_blocks() but is only a subset of the extent on disk. As a result, the contents of extents status cache can get very badly fragmented for certain workloads, such as a random 4k read workload. File size of /mnt/test is 33554432 (8192 blocks of 4096 bytes) ext: logical_offset: physical_offset: length: expected: flags: 0: 0.. 8191: 40960.. 49151: 8192: last,eof $ perf record -e 'ext4:ext4_es_*' /root/bin/fio --name=t --direct=0 --rw=randread --bs=4k --filesize=32M --size=32M --filename=/mnt/test $ perf script | grep ext4_es_insert_extent | head -n 10 fio 131 [000] 13.975421: ext4:ext4_es_insert_extent: dev 253,0 ino 12 es [494/1) mapped 41454 status W fio 131 [000] 13.975939: ext4:ext4_es_insert_extent: dev 253,0 ino 12 es [6064/1) mapped 47024 status W fio 131 [000] 13.976467: ext4:ext4_es_insert_extent: dev 253,0 ino 12 es [6907/1) mapped 47867 status W fio 131 [000] 13.976937: ext4:ext4_es_insert_extent: dev 253,0 ino 12 es [3850/1) mapped 44810 status W fio 131 [000] 13.977440: ext4:ext4_es_insert_extent: dev 253,0 ino 12 es [3292/1) mapped 44252 status W fio 131 [000] 13.977931: ext4:ext4_es_insert_extent: dev 253,0 ino 12 es [6882/1) mapped 47842 status W fio 131 [000] 13.978376: ext4:ext4_es_insert_extent: dev 253,0 ino 12 es [3117/1) mapped 44077 status W fio 131 [000] 13.978957: ext4:ext4_es_insert_extent: dev 253,0 ino 12 es [2896/1) mapped 43856 status W fio 131 [000] 13.979474: ext4:ext4_es_insert_extent: dev 253,0 ino 12 es [7479/1) mapped 48439 status W Fix this by caching the extents for inodes with depth == 0 in ext4_find_extent(). [ Renamed ext4_es_cache_extents() to ext4_cache_extents() since this newly added function is not in extents_cache.c, and to avoid potential visual confusion with ext4_es_cache_extent(). -TYT ] Signed-off-by: Dmitry Monakhov <dmonakhov@gmail.com> Link: https://lore.kernel.org/r/20191106122502.19986-1-dmonakhov@gmail.com Signed-off-by: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-04-21ext4: do not zeroout extents beyond i_disksizeJan Kara
commit 801674f34ecfed033b062a0f217506b93c8d5e8a upstream. We do not want to create initialized extents beyond end of file because for e2fsck it is impossible to distinguish them from a case of corrupted file size / extent tree and so it complains like: Inode 12, i_size is 147456, should be 163840. Fix? no Code in ext4_ext_convert_to_initialized() and ext4_split_convert_extents() try to make sure it does not create initialized extents beyond inode size however they check against inode->i_size which is wrong. They should instead check against EXT4_I(inode)->i_disksize which is the current inode size on disk. That's what e2fsck is going to see in case of crash before all dirty data is written. This bug manifests as generic/456 test failure (with recent enough fstests where fsx got fixed to properly pass FALLOC_KEEP_SIZE_FL flags to the kernel) when run with dioread_lock mount option. CC: stable@vger.kernel.org Fixes: 21ca087a3891 ("ext4: Do not zero out uninitialized extents beyond i_size") Reviewed-by: Lukas Czerner <lczerner@redhat.com> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Theodore Ts'o <tytso@mit.edu> Link: https://lore.kernel.org/r/20200331105016.8674-1-jack@suse.cz Signed-off-by: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-10-05ext4: fix warning inside ext4_convert_unwritten_extents_endioRakesh Pandit
commit e3d550c2c4f2f3dba469bc3c4b83d9332b4e99e1 upstream. Really enable warning when CONFIG_EXT4_DEBUG is set and fix missing first argument. This was introduced in commit ff95ec22cd7f ("ext4: add warning to ext4_convert_unwritten_extents_endio") and splitting extents inside endio would trigger it. Fixes: ff95ec22cd7f ("ext4: add warning to ext4_convert_unwritten_extents_endio") Signed-off-by: Rakesh Pandit <rakesh@tuxera.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu> Cc: stable@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-09-16ext4: don't perform block validity checks on the journal inodeTheodore Ts'o
[ Upstream commit 0a944e8a6c66ca04c7afbaa17e22bf208a8b37f0 ] Since the journal inode is already checked when we added it to the block validity's system zone, if we check it again, we'll just trigger a failure. This was causing failures like this: [ 53.897001] EXT4-fs error (device sda): ext4_find_extent:909: inode #8: comm jbd2/sda-8: pblk 121667583 bad header/extent: invalid extent entries - magic f30a, entries 8, max 340(340), depth 0(0) [ 53.931430] jbd2_journal_bmap: journal block not found at offset 49 on sda-8 [ 53.938480] Aborting journal on device sda-8. ... but only if the system was under enough memory pressure that logical->physical mapping for the journal inode gets pushed out of the extent cache. (This is why it wasn't noticed earlier.) Fixes: 345c0dbf3a30 ("ext4: protect journal inode's blocks using block_validity") Reported-by: Dan Rue <dan.rue@linaro.org> Signed-off-by: Theodore Ts'o <tytso@mit.edu> Tested-by: Naresh Kamboju <naresh.kamboju@linaro.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-05-22ext4: zero out the unused memory region in the extent tree blockSriram Rajagopalan
commit 592acbf16821288ecdc4192c47e3774a4c48bb64 upstream. This commit zeroes out the unused memory region in the buffer_head corresponding to the extent metablock after writing the extent header and the corresponding extent node entries. This is done to prevent random uninitialized data from getting into the filesystem when the extent block is synced. This fixes CVE-2019-11833. Signed-off-by: Sriram Rajagopalan <sriramr@arista.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu> Cc: stable@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-07-29ext4: handle layout changes to pinned DAX mappingsRoss Zwisler
Follow the lead of xfs_break_dax_layouts() and add synchronization between operations in ext4 which remove blocks from an inode (hole punch, truncate down, etc.) and pages which are pinned due to DAX DMA operations. Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Lukas Czerner <lczerner@redhat.com>
2018-07-08Merge tag 'ext4_for_linus_stable' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4 Pull ext4 bugfixes from Ted Ts'o: "Bug fixes for ext4; most of which relate to vulnerabilities where a maliciously crafted file system image can result in a kernel OOPS or hang. At least one fix addresses an inline data bug could be triggered by userspace without the need of a crafted file system (although it does require that the inline data feature be enabled)" * tag 'ext4_for_linus_stable' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: ext4: check superblock mapped prior to committing ext4: add more mount time checks of the superblock ext4: add more inode number paranoia checks ext4: avoid running out of journal credits when appending to an inline file jbd2: don't mark block as modified if the handle is out of credits ext4: never move the system.data xattr out of the inode body ext4: clear i_data in ext4_inode_info when removing inline data ext4: include the illegal physical block in the bad map ext4_error msg ext4: verify the depth of extent tree in ext4_find_extent() ext4: only look at the bg_flags field if it is valid ext4: make sure bitmaps and the inode table don't overlap with bg descriptors ext4: always check block group bounds in ext4_init_block_bitmap() ext4: always verify the magic number in xattr blocks ext4: add corruption check in ext4_xattr_set_entry() ext4: add warn_on_error mount option
2018-06-14ext4: verify the depth of extent tree in ext4_find_extent()Theodore Ts'o
If there is a corupted file system where the claimed depth of the extent tree is -1, this can cause a massive buffer overrun leading to sadness. This addresses CVE-2018-10877. https://bugzilla.kernel.org/show_bug.cgi?id=199417 Signed-off-by: Theodore Ts'o <tytso@mit.edu> Cc: stable@kernel.org
2018-06-12treewide: kzalloc() -> kcalloc()Kees Cook
The kzalloc() function has a 2-factor argument form, kcalloc(). This patch replaces cases of: kzalloc(a * b, gfp) with: kcalloc(a * b, gfp) as well as handling cases of: kzalloc(a * b * c, gfp) with: kzalloc(array3_size(a, b, c), gfp) as it's slightly less ugly than: kzalloc_array(array_size(a, b), c, gfp) This does, however, attempt to ignore constant size factors like: kzalloc(4 * 1024, gfp) though any constants defined via macros get caught up in the conversion. Any factors with a sizeof() of "unsigned char", "char", and "u8" were dropped, since they're redundant. The Coccinelle script used for this was: // Fix redundant parens around sizeof(). @@ type TYPE; expression THING, E; @@ ( kzalloc( - (sizeof(TYPE)) * E + sizeof(TYPE) * E , ...) | kzalloc( - (sizeof(THING)) * E + sizeof(THING) * E , ...) ) // Drop single-byte sizes and redundant parens. @@ expression COUNT; typedef u8; typedef __u8; @@ ( kzalloc( - sizeof(u8) * (COUNT) + COUNT , ...) | kzalloc( - sizeof(__u8) * (COUNT) + COUNT , ...) | kzalloc( - sizeof(char) * (COUNT) + COUNT , ...) | kzalloc( - sizeof(unsigned char) * (COUNT) + COUNT , ...) | kzalloc( - sizeof(u8) * COUNT + COUNT , ...) | kzalloc( - sizeof(__u8) * COUNT + COUNT , ...) | kzalloc( - sizeof(char) * COUNT + COUNT , ...) | kzalloc( - sizeof(unsigned char) * COUNT + COUNT , ...) ) // 2-factor product with sizeof(type/expression) and identifier or constant. @@ type TYPE; expression THING; identifier COUNT_ID; constant COUNT_CONST; @@ ( - kzalloc + kcalloc ( - sizeof(TYPE) * (COUNT_ID) + COUNT_ID, sizeof(TYPE) , ...) | - kzalloc + kcalloc ( - sizeof(TYPE) * COUNT_ID + COUNT_ID, sizeof(TYPE) , ...) | - kzalloc + kcalloc ( - sizeof(TYPE) * (COUNT_CONST) + COUNT_CONST, sizeof(TYPE) , ...) | - kzalloc + kcalloc ( - sizeof(TYPE) * COUNT_CONST + COUNT_CONST, sizeof(TYPE) , ...) | - kzalloc + kcalloc ( - sizeof(THING) * (COUNT_ID) + COUNT_ID, sizeof(THING) , ...) | - kzalloc + kcalloc ( - sizeof(THING) * COUNT_ID + COUNT_ID, sizeof(THING) , ...) | - kzalloc + kcalloc ( - sizeof(THING) * (COUNT_CONST) + COUNT_CONST, sizeof(THING) , ...) | - kzalloc + kcalloc ( - sizeof(THING) * COUNT_CONST + COUNT_CONST, sizeof(THING) , ...) ) // 2-factor product, only identifiers. @@ identifier SIZE, COUNT; @@ - kzalloc + kcalloc ( - SIZE * COUNT + COUNT, SIZE , ...) // 3-factor product with 1 sizeof(type) or sizeof(expression), with // redundant parens removed. @@ expression THING; identifier STRIDE, COUNT; type TYPE; @@ ( kzalloc( - sizeof(TYPE) * (COUNT) * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | kzalloc( - sizeof(TYPE) * (COUNT) * STRIDE + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | kzalloc( - sizeof(TYPE) * COUNT * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | kzalloc( - sizeof(TYPE) * COUNT * STRIDE + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | kzalloc( - sizeof(THING) * (COUNT) * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) | kzalloc( - sizeof(THING) * (COUNT) * STRIDE + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) | kzalloc( - sizeof(THING) * COUNT * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) | kzalloc( - sizeof(THING) * COUNT * STRIDE + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) ) // 3-factor product with 2 sizeof(variable), with redundant parens removed. @@ expression THING1, THING2; identifier COUNT; type TYPE1, TYPE2; @@ ( kzalloc( - sizeof(TYPE1) * sizeof(TYPE2) * COUNT + array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2)) , ...) | kzalloc( - sizeof(TYPE1) * sizeof(THING2) * (COUNT) + array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2)) , ...) | kzalloc( - sizeof(THING1) * sizeof(THING2) * COUNT + array3_size(COUNT, sizeof(THING1), sizeof(THING2)) , ...) | kzalloc( - sizeof(THING1) * sizeof(THING2) * (COUNT) + array3_size(COUNT, sizeof(THING1), sizeof(THING2)) , ...) | kzalloc( - sizeof(TYPE1) * sizeof(THING2) * COUNT + array3_size(COUNT, sizeof(TYPE1), sizeof(THING2)) , ...) | kzalloc( - sizeof(TYPE1) * sizeof(THING2) * (COUNT) + array3_size(COUNT, sizeof(TYPE1), sizeof(THING2)) , ...) ) // 3-factor product, only identifiers, with redundant parens removed. @@ identifier STRIDE, SIZE, COUNT; @@ ( kzalloc( - (COUNT) * STRIDE * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) | kzalloc( - COUNT * (STRIDE) * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) | kzalloc( - COUNT * STRIDE * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | kzalloc( - (COUNT) * (STRIDE) * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) | kzalloc( - COUNT * (STRIDE) * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | kzalloc( - (COUNT) * STRIDE * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | kzalloc( - (COUNT) * (STRIDE) * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | kzalloc( - COUNT * STRIDE * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) ) // Any remaining multi-factor products, first at least 3-factor products, // when they're not all constants... @@ expression E1, E2, E3; constant C1, C2, C3; @@ ( kzalloc(C1 * C2 * C3, ...) | kzalloc( - (E1) * E2 * E3 + array3_size(E1, E2, E3) , ...) | kzalloc( - (E1) * (E2) * E3 + array3_size(E1, E2, E3) , ...) | kzalloc( - (E1) * (E2) * (E3) + array3_size(E1, E2, E3) , ...) | kzalloc( - E1 * E2 * E3 + array3_size(E1, E2, E3) , ...) ) // And then all remaining 2 factors products when they're not all constants, // keeping sizeof() as the second factor argument. @@ expression THING, E1, E2; type TYPE; constant C1, C2, C3; @@ ( kzalloc(sizeof(THING) * C2, ...) | kzalloc(sizeof(TYPE) * C2, ...) | kzalloc(C1 * C2 * C3, ...) | kzalloc(C1 * C2, ...) | - kzalloc + kcalloc ( - sizeof(TYPE) * (E2) + E2, sizeof(TYPE) , ...) | - kzalloc + kcalloc ( - sizeof(TYPE) * E2 + E2, sizeof(TYPE) , ...) | - kzalloc + kcalloc ( - sizeof(THING) * (E2) + E2, sizeof(THING) , ...) | - kzalloc + kcalloc ( - sizeof(THING) * E2 + E2, sizeof(THING) , ...) | - kzalloc + kcalloc ( - (E1) * E2 + E1, E2 , ...) | - kzalloc + kcalloc ( - (E1) * (E2) + E1, E2 , ...) | - kzalloc + kcalloc ( - E1 * E2 + E1, E2 , ...) ) Signed-off-by: Kees Cook <keescook@chromium.org>
2018-04-12ext4: prevent right-shifting extents beyond EXT_MAX_BLOCKSEric Biggers
During the "insert range" fallocate operation, extents starting at the range offset are shifted "right" (to a higher file offset) by the range length. But, as shown by syzbot, it's not validated that this doesn't cause extents to be shifted beyond EXT_MAX_BLOCKS. In that case ->ee_block can wrap around, corrupting the extent tree. Fix it by returning an error if the space between the end of the last extent and EXT4_MAX_BLOCKS is smaller than the range being inserted. This bug can be reproduced by running the following commands when the current directory is on an ext4 filesystem with a 4k block size: fallocate -l 8192 file fallocate --keep-size -o 0xfffffffe000 -l 4096 -n file fallocate --insert-range -l 8192 file Then after unmounting the filesystem, e2fsck reports corruption. Reported-by: syzbot+06c885be0edcdaeab40c@syzkaller.appspotmail.com Fixes: 331573febb6a ("ext4: Add support FALLOC_FL_INSERT_RANGE for fallocate") Cc: stable@vger.kernel.org # v4.2+ Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2018-03-26ext4: fix comments in ext4_swap_extents()zhenwei.pi
"mark_unwritten" in comment and "unwritten" in the function arguments is mismatched. Signed-off-by: zhenwei.pi <zhenwei.pi@youruncloud.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2018-03-22ext4: remove EXT4_STATE_DIOREAD_LOCK flagNikolay Borisov
Commit 16c54688592c ("ext4: Allow parallel DIO reads") reworked the way locking happens around parallel dio reads. This resulted in obviating the need for EXT4_STATE_DIOREAD_LOCK flag and accompanying logic. Currently this amounts to dead code so let's remove it. No functional changes Signed-off-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu> Reviewed-by: Jan Kara <jack@suse.cz>
2017-12-17ext4: fix up remaining files with SPDX cleanupsTheodore Ts'o
A number of ext4 source files were skipped due because their copyright permission statements didn't match the expected text used by the automated conversion utilities. I've added SPDX tags for the rest. While looking at some of these files, I've noticed that we have quite a bit of variation on the licenses that were used --- in particular some of the Red Hat licenses on the jbd2 files use a GPL2+ license, and we have some files that have a LGPL-2.1 license (which was quite surprising). I've not attempted to do any license changes. Even if it is perfectly legal to relicense to GPL 2.0-only for consistency's sake, that should be done with ext4 developer community discussion. Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2017-12-03ext4: fix fdatasync(2) after fallocate(2) operationEryu Guan
Currently, fallocate(2) with KEEP_SIZE followed by a fdatasync(2) then crash, we'll see wrong allocated block number (stat -c %b), the blocks allocated beyond EOF are all lost. fstests generic/468 exposes this bug. Commit 67a7d5f561f4 ("ext4: fix fdatasync(2) after extent manipulation operations") fixed all the other extent manipulation operation paths such as hole punch, zero range, collapse range etc., but forgot the fallocate case. So similarly, fix it by recording the correct journal tid in ext4 inode in fallocate(2) path, so that ext4_sync_file() will wait for the right tid to be committed on fdatasync(2). This addresses the test failure in xfstests test generic/468. Signed-off-by: Eryu Guan <eguan@redhat.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu> Cc: stable@vger.kernel.org
2017-10-06ext4: fix interaction between i_size, fallocate, and delalloc after a crashTheodore Ts'o
If there are pending writes subject to delayed allocation, then i_size will show size after the writes have completed, while i_disksize contains the value of i_size on the disk (since the writes have not been persisted to disk). If fallocate(2) is called with the FALLOC_FL_KEEP_SIZE flag, either with or without the FALLOC_FL_ZERO_RANGE flag set, and the new size after the fallocate(2) is between i_size and i_disksize, then after a crash, if a journal commit has resulted in the changes made by the fallocate() call to be persisted after a crash, but the delayed allocation write has not resolved itself, i_size would not be updated, and this would cause the following e2fsck complaint: Inode 12, end of extent exceeds allowed value (logical block 33, physical block 33441, len 7) This can only take place on a sparse file, where the fallocate(2) call is allocating blocks in a range which is before a pending delayed allocation write which is extending i_size. Since this situation is quite rare, and the window in which the crash must take place is typically < 30 seconds, in practice this condition will rarely happen. Nevertheless, it can be triggered in testing, and in particular by xfstests generic/456. Signed-off-by: Theodore Ts'o <tytso@mit.edu> Reported-by: Amir Goldstein <amir73il@gmail.com> Cc: stable@vger.kernel.org
2017-08-06ext4: fix copy paste error in ext4_swap_extents()Maninder Singh
This bug was found by a static code checker tool for copy paste problems. Signed-off-by: Maninder Singh <maninder1.s@samsung.com> Signed-off-by: Vaneet Narang <v.narang@samsung.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2017-08-05ext4: remove unused mode parameterTahsin Erdogan
ext4_alloc_file_blocks() does not use its mode parameter. Remove it. Signed-off-by: Tahsin Erdogan <tahsin@google.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2017-06-21ext4: call journal revoke when freeing ea_inode blocksTahsin Erdogan
ea_inode contents are treated as metadata, that's why it is journaled during initial writes. Failing to call revoke during freeing could cause user data to be overwritten with original ea_inode contents during journal replay. Signed-off-by: Tahsin Erdogan <tahsin@google.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2017-05-29ext4: fix fdatasync(2) after extent manipulation operationsJan Kara
Currently, extent manipulation operations such as hole punch, range zeroing, or extent shifting do not record the fact that file data has changed and thus fdatasync(2) has a work to do. As a result if we crash e.g. after a punch hole and fdatasync, user can still possibly see the punched out data after journal replay. Test generic/392 fails due to these problems. Fix the problem by properly marking that file data has changed in these operations. CC: stable@vger.kernel.org Fixes: a4bb6b64e39abc0e41ca077725f2a72c868e7622 Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2017-05-26ext4: fix data corruption with EXT4_GET_BLOCKS_ZEROJan Kara
When ext4_map_blocks() is called with EXT4_GET_BLOCKS_ZERO to zero-out allocated blocks and these blocks are actually converted from unwritten extent the following race can happen: CPU0 CPU1 page fault page fault ... ... ext4_map_blocks() ext4_ext_map_blocks() ext4_ext_handle_unwritten_extents() ext4_ext_convert_to_initialized() - zero out converted extent ext4_zeroout_es() - inserts extent as initialized in status tree ext4_map_blocks() ext4_es_lookup_extent() - finds initialized extent write data ext4_issue_zeroout() - zeroes out new extent overwriting data This problem can be reproduced by generic/340 for the fallocated case for the last block in the file. Fix the problem by avoiding zeroing out the area we are mapping with ext4_map_blocks() in ext4_ext_convert_to_initialized(). It is pointless to zero out this area in the first place as the caller asked us to convert the area to initialized because he is just going to write data there before the transaction finishes. To achieve this we delete the special case of zeroing out full extent as that will be handled by the cases below zeroing only the part of the extent that needs it. We also instruct ext4_split_extent() that the middle of extent being split contains data so that ext4_split_extent_at() cannot zero out full extent in case of ENOSPC. CC: stable@vger.kernel.org Fixes: 12735f881952c32b31bc4e433768f18489f79ec9 Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2017-01-08ext4: do not polute the extents cache while shifting extentsRoman Pen
Inside ext4_ext_shift_extents() function ext4_find_extent() is called without EXT4_EX_NOCACHE flag, which should prevent cache population. This leads to oudated offsets in the extents tree and wrong blocks afterwards. Patch fixes the problem providing EXT4_EX_NOCACHE flag for each ext4_find_extents() call inside ext4_ext_shift_extents function. Fixes: 331573febb6a2 Signed-off-by: Roman Pen <roman.penyaev@profitbricks.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu> Cc: Namjae Jeon <namjae.jeon@samsung.com> Cc: Andreas Dilger <adilger.kernel@dilger.ca> Cc: stable@vger.kernel.org
2017-01-08ext4: Include forgotten start block on fallocate insert rangeRoman Pen
While doing 'insert range' start block should be also shifted right. The bug can be easily reproduced by the following test: ptr = malloc(4096); assert(ptr); fd = open("./ext4.file", O_CREAT | O_TRUNC | O_RDWR, 0600); assert(fd >= 0); rc = fallocate(fd, 0, 0, 8192); assert(rc == 0); for (i = 0; i < 2048; i++) *((unsigned short *)ptr + i) = 0xbeef; rc = pwrite(fd, ptr, 4096, 0); assert(rc == 4096); rc = pwrite(fd, ptr, 4096, 4096); assert(rc == 4096); for (block = 2; block < 1000; block++) { rc = fallocate(fd, FALLOC_FL_INSERT_RANGE, 4096, 4096); assert(rc == 0); for (i = 0; i < 2048; i++) *((unsigned short *)ptr + i) = block; rc = pwrite(fd, ptr, 4096, 4096); assert(rc == 4096); } Because start block is not included in the range the hole appears at the wrong offset (just after the desired offset) and the following pwrite() overwrites already existent block, keeping hole untouched. Simple way to verify wrong behaviour is to check zeroed blocks after the test: $ hexdump ./ext4.file | grep '0000 0000' The root cause of the bug is a wrong range (start, stop], where start should be inclusive, i.e. [start, stop]. This patch fixes the problem by including start into the range. But not to break left shift (range collapse) stop points to the beginning of the a block, not to the end. The other not obvious change is an iterator check on validness in a main loop. Because iterator is unsigned the following corner case should be considered with care: insert a block at 0 offset, when stop variables overflows and never becomes less than start, which is 0. To handle this special case iterator is set to NULL to indicate that end of the loop is reached. Fixes: 331573febb6a2 Signed-off-by: Roman Pen <roman.penyaev@profitbricks.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu> Cc: Namjae Jeon <namjae.jeon@samsung.com> Cc: Andreas Dilger <adilger.kernel@dilger.ca> Cc: stable@vger.kernel.org
2016-12-24Replace <asm/uaccess.h> with <linux/uaccess.h> globallyLinus Torvalds
This was entirely automated, using the script by Al: PATT='^[[:blank:]]*#[[:blank:]]*include[[:blank:]]*<asm/uaccess.h>' sed -i -e "s!$PATT!#include <linux/uaccess.h>!" \ $(git grep -l "$PATT"|grep -v ^include/linux/uaccess.h) to do the replacement at the end of the merge window. Requested-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-12-14Merge branch 'for-4.10/fs-unmap' of git://git.kernel.dk/linux-blockLinus Torvalds
Pull fs meta data unmap optimization from Jens Axboe: "A series from Jan Kara, providing a more efficient way for unmapping meta data from in the buffer cache than doing it block-by-block. Provide a general helper that existing callers can use" * 'for-4.10/fs-unmap' of git://git.kernel.dk/linux-block: fs: Remove unmap_underlying_metadata fs: Add helper to clean bdev aliases under a bh and use it ext2: Use clean_bdev_aliases() instead of iteration ext4: Use clean_bdev_aliases() instead of iteration direct-io: Use clean_bdev_aliases() instead of handmade iteration fs: Provide function to unmap metadata for a range of blocks
2016-12-03ext4: remove another test in ext4_alloc_file_blocks()Dan Carpenter
Before commit c3fe493ccdb1 ('ext4: remove unneeded test in ext4_alloc_file_blocks()') then it was possible for "depth" to be -1 but now, it's not possible that it is negative. Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu> Reviewed-by: Jan Kara <jack@suse.cz>
2016-11-14ext4: use current_time() for inode timestampsDeepa Dinamani
CURRENT_TIME_SEC and CURRENT_TIME are not y2038 safe. current_time() will be transitioned to be y2038 safe along with vfs. current_time() returns timestamps according to the granularities set in the super_block. The granularity check in ext4_current_time() to call current_time() or CURRENT_TIME_SEC is not required. Use current_time() directly to obtain timestamps unconditionally, and remove ext4_current_time(). Quota files are assumed to be on the same filesystem. Hence, use current_time() for these files as well. Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu> Reviewed-by: Arnd Bergmann <arnd@arndb.de>
2016-11-13ext4: allow ext4_ext_truncate() to return an errorTheodore Ts'o
Return errors to the caller instead of declaring the file system corrupted. Signed-off-by: Theodore Ts'o <tytso@mit.edu> Reviewed-by: Jan Kara <jack@suse.cz>
2016-11-04ext4: Use clean_bdev_aliases() instead of iterationJan Kara
Use clean_bdev_aliases() instead of iterating through blocks one by one. Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@fb.com>
2016-09-15ext4: create EXT4_MAX_BLOCKS() macroFabian Frederick
Create a macro to calculate length + offset -> maximum blocks This adds more readability. Signed-off-by: Fabian Frederick <fabf@skynet.be> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2016-09-15ext4: remove unneeded test in ext4_alloc_file_blocks()Fabian Frederick
ext4_alloc_file_blocks() is called from ext4_zero_range() and ext4_fallocate() both already testing EXT4_INODE_EXTENTS We can call ext_depth(inode) unconditionnally. [ Added BUG_ON check to make sure ext4_alloc_file_blocks() won't get called for a indirect-mapped inode in the future. -- tytso ] Signed-off-by: Fabian Frederick <fabf@skynet.be> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2016-09-15ext4: fix memory leak in ext4_insert_range()Fabian Frederick
Running xfstests generic/013 with kmemleak gives the following: unreferenced object 0xffff8801d3d27de0 (size 96): comm "fsstress", pid 4941, jiffies 4294860168 (age 53.485s) hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 00 00 01 00 00 00 00 00 ................ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: [<ffffffff818eaaf3>] kmemleak_alloc+0x23/0x40 [<ffffffff81179805>] __kmalloc+0xf5/0x1d0 [<ffffffff8122ef5c>] ext4_find_extent+0x1ec/0x2f0 [<ffffffff8123530c>] ext4_insert_range+0x34c/0x4a0 [<ffffffff81235942>] ext4_fallocate+0x4e2/0x8b0 [<ffffffff81181334>] vfs_fallocate+0x134/0x210 [<ffffffff8118203f>] SyS_fallocate+0x3f/0x60 [<ffffffff818efa9b>] entry_SYSCALL_64_fastpath+0x13/0x8f [<ffffffffffffffff>] 0xffffffffffffffff Problem seems mitigated by dropping refs and freeing path when there's no path[depth].p_ext Cc: stable@vger.kernel.org Signed-off-by: Fabian Frederick <fabf@skynet.be> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2016-07-15ext4: verify extent header depthVegard Nossum
Although the extent tree depth of 5 should enough be for the worst case of 2*32 extents of length 1, the extent tree code does not currently to merge nodes which are less than half-full with a sibling node, or to shrink the tree depth if possible. So it's possible, at least in theory, for the tree depth to be greater than 5. However, even in the worst case, a tree depth of 32 is highly unlikely, and if the file system is maliciously corrupted, an insanely large eh_depth can cause memory allocation failures that will trigger kernel warnings (here, eh_depth = 65280): JBD2: ext4.exe wants too many credits credits:195849 rsv_credits:0 max:256 ------------[ cut here ]------------ WARNING: CPU: 0 PID: 50 at fs/jbd2/transaction.c:293 start_this_handle+0x569/0x580 CPU: 0 PID: 50 Comm: ext4.exe Not tainted 4.7.0-rc5+ #508 Stack: 604a8947 625badd8 0002fd09 00000000 60078643 00000000 62623910 601bf9bc 62623970 6002fc84 626239b0 900000125 Call Trace: [<6001c2dc>] show_stack+0xdc/0x1a0 [<601bf9bc>] dump_stack+0x2a/0x2e [<6002fc84>] __warn+0x114/0x140 [<6002fdff>] warn_slowpath_null+0x1f/0x30 [<60165829>] start_this_handle+0x569/0x580 [<60165d4e>] jbd2__journal_start+0x11e/0x220 [<60146690>] __ext4_journal_start_sb+0x60/0xa0 [<60120a81>] ext4_truncate+0x131/0x3a0 [<60123677>] ext4_setattr+0x757/0x840 [<600d5d0f>] notify_change+0x16f/0x2a0 [<600b2b16>] do_truncate+0x76/0xc0 [<600c3e56>] path_openat+0x806/0x1300 [<600c55c9>] do_filp_open+0x89/0xf0 [<600b4074>] do_sys_open+0x134/0x1e0 [<600b4140>] SyS_open+0x20/0x30 [<6001ea68>] handle_syscall+0x88/0x90 [<600295fd>] userspace+0x3fd/0x500 [<6001ac55>] fork_handler+0x85/0x90 ---[ end trace 08b0b88b6387a244 ]--- [ Commit message modified and the extent tree depath check changed from 5 to 32 -- tytso ] Cc: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2016-06-30ext4: check for extents that wrap aroundVegard Nossum
An extent with lblock = 4294967295 and len = 1 will pass the ext4_valid_extent() test: ext4_lblk_t last = lblock + len - 1; if (len == 0 || lblock > last) return 0; since last = 4294967295 + 1 - 1 = 4294967295. This would later trigger the BUG_ON(es->es_lblk + es->es_len < es->es_lblk) in ext4_es_end(). We can simplify it by removing the - 1 altogether and changing the test to use lblock + len <= lblock, since now if len = 0, then lblock + 0 == lblock and it fails, and if len > 0 then lblock + len > lblock in order to pass (i.e. it doesn't overflow). Fixes: 5946d0893 ("ext4: check for overlapping extents in ext4_valid_extent_entries()") Fixes: 2f974865f ("ext4: check for zero length extent explicitly") Cc: Eryu Guan <guaneryu@gmail.com> Cc: stable@vger.kernel.org Signed-off-by: Phil Turnbull <phil.turnbull@oracle.com> Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2016-05-05ext4: remove unmeetable inconsisteny check from ext4_find_extent()Nicolai Stange
ext4_find_extent(), stripped down to the parts relevant to this patch, reads as ppos = 0; i = depth; while (i) { --i; ++ppos; if (unlikely(ppos > depth)) { ... ret = -EFSCORRUPTED; goto err; } } Due to the loop's bounds, the condition ppos > depth can never be met. Remove this dead code. Signed-off-by: Nicolai Stange <nicstange@gmail.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2016-04-27ext4: remove trailing \n from ext4_warning/ext4_error callsJakub Wilk
Messages passed to ext4_warning() or ext4_error() don't need trailing newlines, because these function add the newlines themselves. Signed-off-by: Jakub Wilk <jwilk@jwilk.net>
2016-04-25ext4: fix jbd2 handle extension in ext4_ext_truncate_extend_restart()Theodore Ts'o
The function jbd2_journal_extend() takes as its argument the number of new credits to be added to the handle. We weren't taking into account the currently unused handle credits; worse, we would try to extend the handle by N credits when it had N credits available. In the case where jbd2_journal_extend() fails because the transaction is too large, when jbd2_journal_restart() gets called, the N credits owned by the handle gets returned to the transaction, and the transaction commit is asynchronously requested, and then start_this_handle() will be able to successfully attach the handle to the current transaction since the required credits are now available. This is mostly harmless, but since ext4_ext_truncate_extend_restart() returns EAGAIN, the truncate machinery will once again try to call ext4_ext_truncate_extend_restart(), which will do the above sequence over and over again until the transaction has committed. This was found while I was debugging a lockup in caused by running xfstests generic/074 in the data=journal case. I'm still not sure why we ended up looping forever, which suggests there may still be another bug hiding in the transaction accounting machinery, but this commit prevents us from looping in the first place. Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2016-03-09ext4: fix misspellings in comments.Adam Buchbinder
Signed-off-by: Adam Buchbinder <adam.buchbinder@gmail.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2016-03-09ext4: return hole from ext4_map_blocks()Jan Kara
Currently, ext4_map_blocks() just returns 0 when it finds a hole and allocation is not requested. However we have all the information available to tell how large the hole actually is and there are callers of ext4_map_blocks() which would save some block-by-block hole iteration if they knew this information. So fill in struct ext4_map_blocks even for holes with the information we have. We keep returning 0 for holes to maintain backward compatibility of the function. Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2016-03-09ext4: factor out determining of hole sizeJan Kara
ext4_ext_put_gap_in_cache() determines hole size in the extent tree, then trims this with possible delayed allocated blocks, and inserts the result into the extent status tree. Factor out determination of the size of the hole in the extent tree as we will need this information in ext4_ext_map_blocks() as well. Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2016-03-08ext4: simplify io_end handling for AIO DIOJan Kara
When mapping blocks for direct IO, we allocate io_end structure before mapping blocks and store pointer to it in the inode. This creates a requirement that any AIO DIO using io_end must be protected by i_mutex. This created problems in the past with dioread_nolock mode which was corrupting io_end pointers. Also io_end is allocated unnecessarily in case where we don't need to convert any extents (which is a common case for example when overwriting file). We fix the problem by allocating io_end only once we return unwritten extent from block mapping function for AIO DIO (so we can save some pointless io_end allocations) and we pass pointer to it in bh->b_private which generic DIO code later passes to our end IO callback. That way we remove any need for global pointer to io_end structure and thus fix the races. The downside of this change is that the checking for unwritten IO in flight in ext4_extents_can_be_merged() is more racy since we now increment i_unwritten / set EXT4_STATE_DIO_UNWRITTEN only after dropping i_data_sem. However the check has been racy already before because ext4_writepages() already increment i_unwritten after dropping i_data_sem and reserved blocks save us from hitting ENOSPC in the worst case. Signed-off-by: Jan Kara <jack@suse.cz>
2016-02-22ext4: trim unused parameter from convert_initialized_extent()Eric Whitney
The flags parameter is also unused. Signed-off-by: Eric Whitney <enwlinux@gmail.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2016-02-12ext4: remove unused parameter "newblock" in convert_initialized_extent()Eryu Guan
The "newblock" parameter is not used in convert_initialized_extent(), remove it. Signed-off-by: Eryu Guan <guaneryu@gmail.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2016-01-22wrappers for ->i_mutex accessAl Viro
parallel to mutex_{lock,unlock,trylock,is_locked,lock_nested}, inode_foo(inode) being mutex_foo(&inode->i_mutex). Please, use those for access to ->i_mutex; over the coming cycle ->i_mutex will become rwsem, with ->lookup() done with it held only shared. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-12-07ext4: implement allocation of pre-zeroed blocksJan Kara
DAX page fault path needs to get blocks that are pre-zeroed to avoid races when two concurrent page faults happen in the same block of a file. Implement support for this in ext4_map_blocks(). Signed-off-by: Jan Kara <jack@suse.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-12-07ext4: provide ext4_issue_zeroout()Jan Kara
Create new function ext4_issue_zeroout() to zeroout contiguous (both logically and physically) part of inode data. We will need to issue zeroout when extent structure is not readily available and this function will allow us to do it without making up fake extent structures. Signed-off-by: Jan Kara <jack@suse.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-12-07ext4: fix races of writeback with punch hole and zero rangeJan Kara
When doing delayed allocation, update of on-disk inode size is postponed until IO submission time. However hole punch or zero range fallocate calls can end up discarding the tail page cache page and thus on-disk inode size would never be properly updated. Make sure the on-disk inode size is updated before truncating page cache. Signed-off-by: Jan Kara <jack@suse.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-12-07ext4: fix races between buffered IO and collapse / insert rangeJan Kara
Current code implementing FALLOC_FL_COLLAPSE_RANGE and FALLOC_FL_INSERT_RANGE is prone to races with buffered writes and page faults. If buffered write or write via mmap manages to squeeze between filemap_write_and_wait_range() and truncate_pagecache() in the fallocate implementations, the written data is simply discarded by truncate_pagecache() although it should have been shifted. Fix the problem by moving filemap_write_and_wait_range() call inside i_mutex and i_mmap_sem. That way we are protected against races with both buffered writes and page faults. Signed-off-by: Jan Kara <jack@suse.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-12-07ext4: move unlocked dio protection from ext4_alloc_file_blocks()Jan Kara
Currently ext4_alloc_file_blocks() was handling protection against unlocked DIO. However we now need to sometimes call it under i_mmap_sem and sometimes not and DIO protection ranks above it (although strictly speaking this cannot currently create any deadlocks). Also ext4_zero_range() was actually getting & releasing unlocked DIO protection twice in some cases. Luckily it didn't introduce any real bug but it was a land mine waiting to be stepped on. So move DIO protection out from ext4_alloc_file_blocks() into the two callsites. Signed-off-by: Jan Kara <jack@suse.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2015-12-07ext4: fix races between page faults and hole punchingJan Kara
Currently, page faults and hole punching are completely unsynchronized. This can result in page fault faulting in a page into a range that we are punching after truncate_pagecache_range() has been called and thus we can end up with a page mapped to disk blocks that will be shortly freed. Filesystem corruption will shortly follow. Note that the same race is avoided for truncate by checking page fault offset against i_size but there isn't similar mechanism available for punching holes. Fix the problem by creating new rw semaphore i_mmap_sem in inode and grab it for writing over truncate, hole punching, and other functions removing blocks from extent tree and for read over page faults. We cannot easily use i_data_sem for this since that ranks below transaction start and we need something ranking above it so that it can be held over the whole truncate / hole punching operation. Also remove various workarounds we had in the code to reduce race window when page fault could have created pages with stale mapping information. Signed-off-by: Jan Kara <jack@suse.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>