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2016-07-14ext4: fix reference counting bug on block allocation errorVegard Nossum
If we hit this error when mounted with errors=continue or errors=remount-ro: EXT4-fs error (device loop0): ext4_mb_mark_diskspace_used:2940: comm ext4.exe: Allocating blocks 5090-6081 which overlap fs metadata then ext4_mb_new_blocks() will call ext4_mb_release_context() and try to continue. However, ext4_mb_release_context() is the wrong thing to call here since we are still actually using the allocation context. Instead, just error out. We could retry the allocation, but there is a possibility of getting stuck in an infinite loop instead, so this seems safer. [ Fixed up so we don't return EAGAIN to userspace. --tytso ] Fixes: 8556e8f3b6 ("ext4: Don't allow new groups to be added during block allocation") Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Cc: stable@vger.kernel.org
2016-07-14chardev: add missing line break in pr_warnFengguang Wu
To fix super long dmesg error lines like CHRDEV "dummy_stm.0" major number 224 goes below the dynamic allocation rangeCHRDEV "dummy_stm.1" major number 223 goes below the dynamic allocation rangeswapper: page allocation failure: order:8, mode:0x26040c0(GFP_KERNEL|__GFP_COMP|__GFP_NOTRACK) After fix, it should look like CHRDEV "dummy_stm.0" major number 224 goes below the dynamic allocation range CHRDEV "dummy_stm.1" major number 223 goes below the dynamic allocation range swapper: page allocation failure: order:8, mode:0x26040c0(GFP_KERNEL|__GFP_COMP|__GFP_NOTRACK) Reported-by: Philip Li <philip.li@intel.com> Signed-off-by: Fengguang Wu <fengguang.wu@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-07-12pmem: kill __pmem address spaceDan Williams
The __pmem address space was meant to annotate codepaths that touch persistent memory and need to coordinate a call to wmb_pmem(). Now that wmb_pmem() is gone, there is little need to keep this annotation. Cc: Christoph Hellwig <hch@lst.de> Cc: Ross Zwisler <ross.zwisler@linux.intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2016-07-12fs/dax: remove wmb_pmem()Dan Williams
Flushing posted-write queues is now deferred to REQ_FLUSH context, or otherwise handled by an ADR event at the platform level. Cc: Ross Zwisler <ross.zwisler@linux.intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2016-07-12cifs: Check for existing directory when opening file with O_CREATSachin Prabhu
When opening a file with O_CREAT flag, check to see if the file opened is an existing directory. This prevents the directory from being opened which subsequently causes a crash when the close function for directories cifs_closedir() is called which frees up the file->private_data memory while the file is still listed on the open file list for the tcon. Signed-off-by: Sachin Prabhu <sprabhu@redhat.com> Signed-off-by: Steve French <smfrench@gmail.com> CC: Stable <stable@vger.kernel.org> Reported-by: Xiaoli Feng <xifeng@redhat.com>
2016-07-12GFS2: Check rs_free with rd_rsspin protectionBob Peterson
For the last process to close a file opened for write, function gfs2_rsqa_delete was deleting the file's inode's block reservation out of the rgrp reservations tree. Then it was checking to make sure rs_free was 0, but it was performing the check outside the protection of rd_rsspin spin_lock. The rd_rsspin spin_lock protection is needed to prevent a race between the process freeing the reservation and another who is allocating a new set of blocks inside the same rgrp for the same inode, thus changing its value. Signed-off-by: Bob Peterson <rpeterso@redhat.com>
2016-07-12Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull vfs fixes from Al Viro. * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: posix_acl: de-union a_refcount and a_rcu nfs_atomic_open(): prevent parallel nfs_lookup() on a negative hashed Use the right predicate in ->atomic_open() instances
2016-07-11Add MF-Symlinks support for SMB 2.0Sachin Prabhu
We should be able to use the same helper functions used for SMB 2.1 and later versions. Signed-off-by: Sachin Prabhu <sprabhu@redhat.com> Signed-off-by: Steve French <smfrench@gmail.com>
2016-07-10ext4 crypto: migrate into vfs's crypto engineJaegeuk Kim
This patch removes the most parts of internal crypto codes. And then, it modifies and adds some ext4-specific crypt codes to use the generic facility. Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2016-07-10configfs: don't set buffer_needs_fill to zero if show() returns errorTal Shorer
A confgifs attribute's show() callback is called once the first time the user attempts to read from it. If it returns an error, that error is returned to the user. However, the open file's buffer_needs_fill is still set to zero and consecutive read() calls will find an empty buffer that doesn't need filling and return 0 to the user. This could give the user the wrong impression that the attribute was read successfully. Fix this by not setting buffer_needs_fill if show() returns an error, making consecutive read() calls call show() again and either get an error again or get data. Signed-off-by: Tal Shorer <tal.shorer@gmail.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
2016-07-08Merge branch 'topic/cec' into patchworkMauro Carvalho Chehab
* topic/cec: [media] DocBook/media: add CEC documentation [media] s5p_cec: get rid of an unused var [media] move s5p-cec to staging [media] vivid: add CEC emulation [media] cec: s5p-cec: Add s5p-cec driver [media] cec: adv7511: add cec support [media] cec: adv7842: add cec support [media] cec: adv7604: add cec support [media] cec: add compat32 ioctl support [media] cec/TODO: add TODO file so we know why this is still in staging [media] cec: add HDMI CEC framework (api) [media] cec: add HDMI CEC framework (adapter) [media] cec: add HDMI CEC framework (core) [media] cec-funcs.h: static inlines to pack/unpack CEC messages [media] cec.h: add cec header [media] cec-edid: add module for EDID CEC helper functions [media] cec.txt: add CEC framework documentation [media] rc: Add HDMI CEC protocol handling
2016-07-08f2fs: avoid mark_inode_dirtyJaegeuk Kim
Let's check inode's dirtiness before calling mark_inode_dirty. Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2016-07-08f2fs: move i_size_write in f2fs_write_endJaegeuk Kim
We don't need to do i_size_write under page lock. Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2016-07-08f2fs: fix to avoid redundant discard during fstrimChao Yu
With below test steps, f2fs will issue redundant discard when doing fstrim, the reason is that we issue discards for both prefree segments and consecutive freed region user wants to trim, part regions they covered are overlapped, here, we change to do not to issue any discards for prefree segments in trimmed range. 1. mount -t f2fs -o discard /dev/zram0 /mnt/f2fs 2. fstrim -o 0 -l 3221225472 -m 2097152 -v /mnt/f2fs/ 3. dd if=/dev/zero of=/mnt/f2fs/a bs=2M count=1 4. dd if=/dev/zero of=/mnt/f2fs/b bs=1M count=1 5. sync 6. rm /mnt/f2fs/a /mnt/f2fs/b 7. fstrim -o 0 -l 3221225472 -m 2097152 -v /mnt/f2fs/ Before: <...>-5428 [001] ...1 9511.052125: f2fs_issue_discard: dev = (251,0), blkstart = 0x2200, blklen = 0x200 <...>-5428 [001] ...1 9511.052787: f2fs_issue_discard: dev = (251,0), blkstart = 0x2200, blklen = 0x300 After: <...>-6764 [000] ...1 9720.382504: f2fs_issue_discard: dev = (251,0), blkstart = 0x2200, blklen = 0x300 Signed-off-by: Chao Yu <yuchao0@huawei.com> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2016-07-08f2fs: avoid mismatching block range for discardYunlei He
This patch skip discard block range smaller than trim_minlen, and can not be merged by neighbour Signed-off-by: Yunlei He <heyunlei@huawei.com> Reviewed-by: Chao Yu <yuchao0@huawei.com> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2016-07-08f2fs: fix incorrect f_bfree calculation in ->statfsChao Yu
As manual described, f_bfree indicates total free blocks in fs, in f2fs, it includes two parts: visible free blocks and over-provision blocks. This patch corrrects the calculation. fsblkcnt_t f_bfree; /* free blocks in fs */ Signed-off-by: Chao Yu <yuchao0@huawei.com> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2016-07-08f2fs: use percpu_rw_semaphoreJaegeuk Kim
This patch replaces rw_semaphore with percpu_rw_semaphore for: sbi->cp_rwsem nm_i->nat_tree_lock Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2016-07-08f2fs: skip to check the block address of node pageJaegeuk Kim
If the node page is up-to-date, it should be alive. Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2016-07-08f2fs: shrink critical region in spin_lockJaegeuk Kim
This patch shrinks the critical region in spin_lock. Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2016-07-08f2fs: call SetPageUptodate if neededJaegeuk Kim
SetPageUptodate() issues memory barrier, resulting in performance degrdation. Let's avoid that. Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2016-07-08f2fs: introduce f2fs_set_page_dirty_nobufferJaegeuk Kim
This patch adds f2fs_set_page_dirty_nobuffer() copied from __set_page_dirty_buffer. When appending 4KB blocks in f2fs on pmem with multiple cores, this improves the overall performance. Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2016-07-08f2fs: remove unnecessary goto statementTiezhu Yang
When base_addr is NULL, there is no need to call kzfree, it should return -ENOMEM directly. Additionally, it is better to initialize variable 'error' with 0. Signed-off-by: Tiezhu Yang <kernelpatch@126.com> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2016-07-08f2fs: add nodiscard mount optionChao Yu
This patch adds 'nodiscard' mount option. Signed-off-by: Chao Yu <yuchao0@huawei.com> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2016-07-08f2fs: fix to redirty page if fail to gc data pageChao Yu
If we fail to move data page during foreground GC, we should give another chance to writeback that page which was set dirty previously by writer. Signed-off-by: Chao Yu <yuchao0@huawei.com> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2016-07-08f2fs: fix to detect truncation prior rather than EIO during readChao Yu
In procedure of synchonized read, after sending out the read request, reader will try to lock the page for waiting device to finish the read jobs and unlock the page, but meanwhile, truncater will race with reader, so after reader get lock of the page, it should check page's mapping to detect whether someone has truncated the page in advance, then reader has the chance to do the retry if truncation was done, otherwise read can be failed due to previous condition check. Signed-off-by: Chao Yu <yuchao0@huawei.com> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2016-07-08f2fs: fix to avoid reading out encrypted data in page cacheChao Yu
For encrypted inode, if user overwrites data of the inode, f2fs will read encrypted data into page cache, and then do the decryption. However reader can race with overwriter, and it will see encrypted data which has not been decrypted by overwriter yet. Fix it by moving decrypting work to background and keep page non-uptodated until data is decrypted. Thread A Thread B - f2fs_file_write_iter - __generic_file_write_iter - generic_perform_write - f2fs_write_begin - f2fs_submit_page_bio - generic_file_read_iter - do_generic_file_read - lock_page_killable - unlock_page - copy_page_to_iter hit the encrypted data in updated page - lock_page - fscrypt_decrypt_page Signed-off-by: Chao Yu <yuchao0@huawei.com> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2016-07-08Merge tag 'ecryptfs-4.7-rc7-fixes' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tyhicks/ecryptfs Pull eCryptfs fixes from Tyler Hicks: "Provide a more concise fix for CVE-2016-1583: - Additionally fixes linux-stable regressions caused by the cherry-picking of the original fix Some very minor changes that have queued up: - Fix typos in code comments - Remove unnecessary check for NULL before destroying kmem_cache" * tag 'ecryptfs-4.7-rc7-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tyhicks/ecryptfs: ecryptfs: don't allow mmap when the lower fs doesn't support it Revert "ecryptfs: forbid opening files without mmap handler" ecryptfs: fix spelling mistakes eCryptfs: fix typos in comment ecryptfs: drop null test before destroy functions
2016-07-08ecryptfs: don't allow mmap when the lower fs doesn't support itJeff Mahoney
There are legitimate reasons to disallow mmap on certain files, notably in sysfs or procfs. We shouldn't emulate mmap support on file systems that don't offer support natively. CVE-2016-1583 Signed-off-by: Jeff Mahoney <jeffm@suse.com> Cc: stable@vger.kernel.org [tyhicks: clean up f_op check by using ecryptfs_file_to_lower()] Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
2016-07-07Revert "ecryptfs: forbid opening files without mmap handler"Jeff Mahoney
This reverts commit 2f36db71009304b3f0b95afacd8eba1f9f046b87. It fixed a local root exploit but also introduced a dependency on the lower file system implementing an mmap operation just to open a file, which is a bit of a heavy hammer. The right fix is to have mmap depend on the existence of the mmap handler instead. Signed-off-by: Jeff Mahoney <jeffm@suse.com> Cc: stable@vger.kernel.org Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
2016-07-07Merge branch 'for-linus' of git://git.kernel.dk/linux-blockLinus Torvalds
Pull block IO fixes from Jens Axboe: "Three small fixes that have been queued up and tested for this series: - A bug fix for xen-blkfront from Bob Liu, fixing an issue with incomplete requests during migration. - A fix for an ancient issue in retrieving the IO priority of a different PID than self, preventing that task from going away while we access it. From Omar. - A writeback fix from Tahsin, fixing a case where we'd call ihold() with a zero ref count inode" * 'for-linus' of git://git.kernel.dk/linux-block: block: fix use-after-free in sys_ioprio_get() writeback: inode cgroup wb switch should not call ihold() xen-blkfront: save uncompleted reqs in blkfront_resume()
2016-07-07Merge tag 'configfs-for-4.7' of git://git.infradead.org/users/hch/configfsLinus Torvalds
Pull configfs fix from Christoph Hellwig: "A fix from Marek for ppos handling in configfs_write_bin_file, which was introduced in Linux 4.5, but didn't have any users until recently" * tag 'configfs-for-4.7' of git://git.infradead.org/users/hch/configfs: configfs: Remove ppos increment in configfs_write_bin_file
2016-07-07Merge branch 'timers/fast-wheel' into timers/coreIngo Molnar
2016-07-06f2fs: avoid latency-critical readahead of node pagesJaegeuk Kim
The f2fs_map_blocks is very related to the performance, so let's avoid any latency to read ahead node pages. Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2016-07-06f2fs: avoid writing node/metapages during writesJaegeuk Kim
Let's keep more node/meta pages in run time. Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2016-07-06f2fs: produce more nids and reduce readahead natsJaegeuk Kim
The readahead nat pages are more likely to be reclaimed quickly, so it'd better to gather more free nids in advance. And, let's keep some free nids as much as possible. Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2016-07-06f2fs: detect host-managed SMR by feature flagJaegeuk Kim
If mkfs.f2fs gives a feature flag for host-managed SMR, we can set mode=lfs by default. Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2016-07-06f2fs: call update_inode_page for orphan inodesJaegeuk Kim
Let's store orphan inode pages right away. Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2016-07-06f2fs: report error for f2fs_parent_dirJaegeuk Kim
If there is no dentry, we can report its error correctly. Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
2016-07-06Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller
Conflicts: drivers/net/ethernet/mellanox/mlx5/core/en.h drivers/net/ethernet/mellanox/mlx5/core/en_main.c drivers/net/usb/r8152.c All three conflicts were overlapping changes. Signed-off-by: David S. Miller <davem@davemloft.net>
2016-07-05ext2: fix filesystem deadlock while reading corrupted xattr blockCarlos Maiolino
This bug can be reproducible with fsfuzzer, although, I couldn't reproduce it 100% of my tries, it is quite easily reproducible. During the deletion of an inode, ext2_xattr_delete_inode() does not check if the block pointed by EXT2_I(inode)->i_file_acl is a valid data block, this might lead to a deadlock, when i_file_acl == 1, and the filesystem block size is 1024. In that situation, ext2_xattr_delete_inode, will load the superblock's buffer head (instead of a valid i_file_acl block), and then lock that buffer head, which, ext2_sync_super will also try to lock, making the filesystem deadlock in the following stack trace: root 17180 0.0 0.0 113660 660 pts/0 D+ 07:08 0:00 rmdir /media/test/dir1 [<ffffffff8125da9f>] __sync_dirty_buffer+0xaf/0x100 [<ffffffff8125db03>] sync_dirty_buffer+0x13/0x20 [<ffffffffa03f0d57>] ext2_sync_super+0xb7/0xc0 [ext2] [<ffffffffa03f10b9>] ext2_error+0x119/0x130 [ext2] [<ffffffffa03e9d93>] ext2_free_blocks+0x83/0x350 [ext2] [<ffffffffa03f3d03>] ext2_xattr_delete_inode+0x173/0x190 [ext2] [<ffffffffa03ee9e9>] ext2_evict_inode+0xc9/0x130 [ext2] [<ffffffff8123fd23>] evict+0xb3/0x180 [<ffffffff81240008>] iput+0x1b8/0x240 [<ffffffff8123c4ac>] d_delete+0x11c/0x150 [<ffffffff8122fa7e>] vfs_rmdir+0xfe/0x120 [<ffffffff812340ee>] do_rmdir+0x17e/0x1f0 [<ffffffff81234dd6>] SyS_rmdir+0x16/0x20 [<ffffffff81838cf2>] entry_SYSCALL_64_fastpath+0x1a/0xa4 [<ffffffffffffffff>] 0xffffffffffffffff Fix this by using the same approach ext4 uses to test data blocks validity, implementing ext2_data_block_valid. An another possibility when the superblock is very corrupted, is that i_file_acl is 1, block_count is 1 and first_data_block is 0. For such situations, we might have i_file_acl pointing to a 'valid' block, but still step over the superblock. The approach I used was to also test if the superblock is not in the range described by ext2_data_block_valid() arguments Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2016-07-05ext4: fix project quota accounting without quota limits enabledWang Shilong
We should always transfer quota accounting, regardless of whether quota limits are enabled. Steps to reproduce: # mkfs.ext4 /dev/sda4 -O quota,project # mount /dev/sda4 /mnt/test # cp /bin/bash /mnt/test # chattr -p 123 /mnt/test/bash # quota -v -P 123 Signed-off-by: Wang Shilong <wshilong@ddn.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2016-07-05ext4: validate s_reserved_gdt_blocks on mountTheodore Ts'o
If s_reserved_gdt_blocks is extremely large, it's possible for ext4_init_block_bitmap(), which is called when ext4 sets up an uninitialized block bitmap, to corrupt random kernel memory. Add the same checks which e2fsck has --- it must never be larger than blocksize / sizeof(__u32) --- and then add a backup check in ext4_init_block_bitmap() in case the superblock gets modified after the file system is mounted. Reported-by: Vegard Nossum <vegard.nossum@oracle.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu> Cc: stable@vger.kernel.org
2016-07-05ext4: remove unused page_idxyalin wang
Signed-off-by: yalin wang <yalin.wang2010@gmail.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu> Reviewed-by: Jan Kara <jack@suse.com>
2016-07-05dquot: For now explicitly don't support filesystems outside of init_user_nsEric W. Biederman
Mostly supporting filesystems outside of init_user_ns is s/&init_usre_ns/dquot->dq_sb->s_user_ns/. An actual need for supporting quotas on filesystems outside of s_user_ns is quite a ways away and to be done responsibily needs an audit on what can happen with hostile quota files. Until that audit is complete don't attempt to support quota files on filesystems outside of s_user_ns. Cc: Jan Kara <jack@suse.cz> Acked-by: Seth Forshee <seth.forshee@canonical.com> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2016-07-05quota: Handle quota data stored in s_user_ns in quota_setxquotaEric W. Biederman
In Q_XSETQLIMIT use sb->s_user_ns to detect when we are dealing with the filesystems notion of id 0. Cc: Jan Kara <jack@suse.cz> Acked-by: Seth Forshee <seth.forshee@canonical.com> Inspired-by: Seth Forshee <seth.forshee@canonical.com> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2016-07-05quota: Ensure qids map to the filesystemEric W. Biederman
Introduce the helper qid_has_mapping and use it to ensure that the quota system only considers qids that map to the filesystems s_user_ns. In practice for quota supporting filesystems today this is the exact same check as qid_valid. As only 0xffffffff aka (qid_t)-1 does not map into init_user_ns. Replace the qid_valid calls with qid_has_mapping as values come in from userspace. This is harmless today and it prepares the quota system to work on filesystems with quotas but mounted by unprivileged users. Call qid_has_mapping from dqget. This ensures the passed in qid has a prepresentation on the underlying filesystem. Previously this was unnecessary as filesystesm never had qids that could not map. With the introduction of filesystems outside of s_user_ns this will not remain true. All of this ensures the quota code never has to deal with qids that don't map to the underlying filesystem. Cc: Jan Kara <jack@suse.cz> Acked-by: Seth Forshee <seth.forshee@canonical.com> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2016-07-05vfs: Don't create inodes with a uid or gid unknown to the vfsEric W. Biederman
It is expected that filesystems can not represent uids and gids from outside of their user namespace. Keep things simple by not even trying to create filesystem nodes with non-sense uids and gids. Acked-by: Seth Forshee <seth.forshee@canonical.com> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2016-07-05vfs: Don't modify inodes with a uid or gid unknown to the vfsEric W. Biederman
When a filesystem outside of init_user_ns is mounted it could have uids and gids stored in it that do not map to init_user_ns. The plan is to allow those filesystems to set i_uid to INVALID_UID and i_gid to INVALID_GID for unmapped uids and gids and then to handle that strange case in the vfs to ensure there is consistent robust handling of the weirdness. Upon a careful review of the vfs and filesystems about the only case where there is any possibility of confusion or trouble is when the inode is written back to disk. In that case filesystems typically read the inode->i_uid and inode->i_gid and write them to disk even when just an inode timestamp is being updated. Which leads to a rule that is very simple to implement and understand inodes whose i_uid or i_gid is not valid may not be written. In dealing with access times this means treat those inodes as if the inode flag S_NOATIME was set. Reads of the inodes appear safe and useful, but any write or modification is disallowed. The only inode write that is allowed is a chown that sets the uid and gid on the inode to valid values. After such a chown the inode is normal and may be treated as such. Denying all writes to inodes with uids or gids unknown to the vfs also prevents several oddball cases where corruption would have occurred because the vfs does not have complete information. One problem case that is prevented is attempting to use the gid of a directory for new inodes where the directories sgid bit is set but the directories gid is not mapped. Another problem case avoided is attempting to update the evm hash after setxattr, removexattr, and setattr. As the evm hash includeds the inode->i_uid or inode->i_gid not knowning the uid or gid prevents a correct evm hash from being computed. evm hash verification also fails when i_uid or i_gid is unknown but that is essentially harmless as it does not cause filesystem corruption. Acked-by: Seth Forshee <seth.forshee@canonical.com> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2016-07-05nfs_atomic_open(): prevent parallel nfs_lookup() on a negative hashedAl Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-07-05Use the right predicate in ->atomic_open() instancesAl Viro
->atomic_open() can be given an in-lookup dentry *or* a negative one found in dcache. Use d_in_lookup() to tell one from another, rather than d_unhashed(). Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>