- 22 8月, 2014 13 次提交
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由 Chao Yu 提交于
Theoretically, our total inodes number is the same as total node number, but there are three node ids are reserved in f2fs, they are 0, 1 (node nid), and 2 (meta nid), and they should never be used by user, so our total/free inode number calculated in ->statfs is wrong. This patch indroduces F2FS_RESERVED_NODE_NUM and then fixes this issue by recalculating total/free inode number with the macro. Signed-off-by: NChao Yu <chao2.yu@samsung.com> Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>
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由 Jaegeuk Kim 提交于
Refer the following patch. commit 7177a9c4 Author: Miklos Szeredi <mszeredi@suse.cz> Date: Wed Jul 23 15:15:30 2014 +0200 fs: call rename2 if exists Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>
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由 Jaegeuk Kim 提交于
This patch checks inline_data one more time under the inode page lock whether its inline_data is converted or not. Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>
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由 Jaegeuk Kim 提交于
I think we need to let the dirty node pages remain in the page cache instead of rewriting them in their places. So, after done with successful recovery, write_checkpoint will flush all of them through the normal write path. Through this, we can avoid potential error cases in terms of block allocation. Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>
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由 Jaegeuk Kim 提交于
The init_inode_metadata calls truncate_blocks when error is occurred. The callers holds f2fs_lock_op, so we should not call it again in truncate_blocks. Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>
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由 Jaegeuk Kim 提交于
Any checkpoint should not be done during the core roll-forward procedure. Especially, it includes error cases too. Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>
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由 Jaegeuk Kim 提交于
This patch adds WARN_ON when f2fs_bug_on is disable to see kernel messages. Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>
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由 Jaegeuk Kim 提交于
There are two rules when EIO is occurred. 1. don't write any checkpoint data to preserve the previous checkpoint 2. don't lose the cached dentry/node/meta pages So, at first, this patch adds set_page_dirty in f2fs_write_end_io's failure. Then, writing checkpoint/dentry/node blocks is not allowed. Note that, for the data pages, we can't just throw away by redirtying them. Otherwise, kworker can fall into infinite loop to flush them. (Ref. xfstests/019) Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>
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由 Jaegeuk Kim 提交于
It needs to check s_dirty under cp_mutex, since s_dirty is reset under that mutex. And previous condition was not correct, since we can omit doing checkpoint when checkpoint was done followed by all the node pages were written back. Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>
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由 Jaegeuk Kim 提交于
This patch fixes missing unlock_page when a node page is redirtied out. Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>
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由 Jaegeuk Kim 提交于
This patch adds f2fs_cp_error for readability. Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>
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由 Jaegeuk Kim 提交于
This patch gives another chance to try mount process when we encounter an error. This makes an effect on the roll-forward recovery failures as well. Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>
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由 Jaegeuk Kim 提交于
The generic_shutdown_super calls sync_filesystem, evict_inode, and then f2fs_put_super. In f2fs_evict_inode, we remain some dirty inode information so we should release them at f2fs_put_super. Reviewed-by: NChao Yu <chao2.yu@samsung.com> Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>
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- 20 8月, 2014 9 次提交
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由 Jaegeuk Kim 提交于
This is the errorneous scenario. 1. write data 2. do checkpoint 3. produce some dirty node pages by the gc thread 4. write back dirty node pages 5. f2fs_put_super will skip the checkpoint, since dirty count for node pages is zero. This patch removes such the wrong condition check. Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>
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由 Jaegeuk Kim 提交于
During the recovery, if an error like EIO or ENOMEM, f2fs_bug_on should skip. Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>
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由 Jaegeuk Kim 提交于
This patch fixes not to skip xattr recovery and inline xattr/data recovery order. Reviewed-by: NChao Yu <chao2.yu@samsung.com> Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>
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由 Jaegeuk Kim 提交于
During the recovery, we should clear the inline_xattr flag if its xattr node block is recovered. Reviewed-by: NChao Yu <chao2.yu@samsung.com> Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>
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由 Jaegeuk Kim 提交于
If an inode are fsynced multiple times with fsync & dent marks, this inode will set FI_INC_LINK at find_fsync_dnodes during the recovery. But, in recover_inode, recover_dentry doesn't clear that flag when multiple hits were occurred. So this patch removes the flag for the further consistency. Reviewed-by: NChao Yu <chao2.yu@samsung.com> Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>
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由 Jaegeuk Kim 提交于
If a new inode page is needed for recover_dentry, we should assing i_inline as zero. Reviewed-by: NChao Yu <chao2.yu@samsung.com> Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>
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由 Jaegeuk Kim 提交于
This patch adds a parentheses to make clear for condition check. And also it changes the return type for better meanings. Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>
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由 Jaegeuk Kim 提交于
If mkwrite is called to an inode having inline_data, it can overwrite the data index space as NEW_ADDR. (e.g., the first 4 bytes are coincidently zero) Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>
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由 arter97 提交于
Fix typo and some grammatical errors. The words "filesystem" and "readahead" are being used without the space treewide. Signed-off-by: NPark Ju Hyung <qkrwngud825@gmail.com> Signed-off-by: NJaegeuk Kim <jaegeuk@kernel.org>
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- 15 8月, 2014 9 次提交
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由 Chris Mason 提交于
Truncates and renames are often used to replace old versions of a file with new versions. Applications often expect this to be an atomic replacement, even if they haven't done anything to make sure the new version is fully on disk. Btrfs has strict flushing in place to make sure that renaming over an old file with a new file will fully flush out the new file before allowing the transaction commit with the rename to complete. This ordering means the commit code needs to be able to lock file pages, and there are a few paths in the filesystem where we will try to end a transaction with the page lock held. It's rare, but these things can deadlock. This patch removes the ordered flushes and switches to a best effort filemap_flush like ext4 uses. It's not perfect, but it should fix the deadlocks. Signed-off-by: NChris Mason <clm@fb.com>
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由 Filipe Manana 提交于
Under rare circumstances we can end up leaving 2 versions of a checksum for the same file extent range. The reason for this is that after calling btrfs_next_leaf we process slot 0 of the leaf it returns, instead of processing the slot set in path->slots[0]. Most of the time (by far) path->slots[0] is 0, but after btrfs_next_leaf() releases the path and before it searches for the next leaf, another task might cause a split of the next leaf, which migrates some of its keys to the leaf we were processing before calling btrfs_next_leaf(). In this case btrfs_next_leaf() returns again the same leaf but with path->slots[0] having a slot number corresponding to the first new key it got, that is, a slot number that didn't exist before calling btrfs_next_leaf(), as the leaf now has more keys than it had before. So we must really process the returned leaf starting at path->slots[0] always, as it isn't always 0, and the key at slot 0 can have an offset much lower than our search offset/bytenr. For example, consider the following scenario, where we have: sums->bytenr: 40157184, sums->len: 16384, sums end: 40173568 four 4kb file data blocks with offsets 40157184, 40161280, 40165376, 40169472 Leaf N: slot = 0 slot = btrfs_header_nritems() - 1 |-------------------------------------------------------------------| | [(CSUM CSUM 39239680), size 8] ... [(CSUM CSUM 40116224), size 4] | |-------------------------------------------------------------------| Leaf N + 1: slot = 0 slot = btrfs_header_nritems() - 1 |--------------------------------------------------------------------| | [(CSUM CSUM 40161280), size 32] ... [((CSUM CSUM 40615936), size 8 | |--------------------------------------------------------------------| Because we are at the last slot of leaf N, we call btrfs_next_leaf() to find the next highest key, which releases the current path and then searches for that next key. However after releasing the path and before finding that next key, the item at slot 0 of leaf N + 1 gets moved to leaf N, due to a call to ctree.c:push_leaf_left() (via ctree.c:split_leaf()), and therefore btrfs_next_leaf() will returns us a path again with leaf N but with the slot pointing to its new last key (CSUM CSUM 40161280). This new version of leaf N is then: slot = 0 slot = btrfs_header_nritems() - 2 slot = btrfs_header_nritems() - 1 |----------------------------------------------------------------------------------------------------| | [(CSUM CSUM 39239680), size 8] ... [(CSUM CSUM 40116224), size 4] [(CSUM CSUM 40161280), size 32] | |----------------------------------------------------------------------------------------------------| And incorrecly using slot 0, makes us set next_offset to 39239680 and we jump into the "insert:" label, which will set tmp to: tmp = min((sums->len - total_bytes) >> blocksize_bits, (next_offset - file_key.offset) >> blocksize_bits) = min((16384 - 0) >> 12, (39239680 - 40157184) >> 12) = min(4, (u64)-917504 = 18446744073708634112 >> 12) = 4 and ins_size = csum_size * tmp = 4 * 4 = 16 bytes. In other words, we insert a new csum item in the tree with key (CSUM_OBJECTID CSUM_KEY 40157184 = sums->bytenr) that contains the checksums for all the data (4 blocks of 4096 bytes each = sums->len). Which is wrong, because the item with key (CSUM CSUM 40161280) (the one that was moved from leaf N + 1 to the end of leaf N) contains the old checksums of the last 12288 bytes of our data and won't get those old checksums removed. So this leaves us 2 different checksums for 3 4kb blocks of data in the tree, and breaks the logical rule: Key_N+1.offset >= Key_N.offset + length_of_data_its_checksums_cover An obvious bad effect of this is that a subsequent csum tree lookup to get the checksum of any of the blocks with logical offset of 40161280, 40165376 or 40169472 (the last 3 4kb blocks of file data), will get the old checksums. Cc: stable@vger.kernel.org Signed-off-by: NFilipe Manana <fdmanana@suse.com> Signed-off-by: NChris Mason <clm@fb.com>
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由 Takashi Iwai 提交于
We've got bug reports that btrfs crashes when quota is enabled on 32bit kernel, typically with the Oops like below: BUG: unable to handle kernel NULL pointer dereference at 00000004 IP: [<f9234590>] find_parent_nodes+0x360/0x1380 [btrfs] *pde = 00000000 Oops: 0000 [#1] SMP CPU: 0 PID: 151 Comm: kworker/u8:2 Tainted: G S W 3.15.2-1.gd43d97e-default #1 Workqueue: btrfs-qgroup-rescan normal_work_helper [btrfs] task: f1478130 ti: f147c000 task.ti: f147c000 EIP: 0060:[<f9234590>] EFLAGS: 00010213 CPU: 0 EIP is at find_parent_nodes+0x360/0x1380 [btrfs] EAX: f147dda8 EBX: f147ddb0 ECX: 00000011 EDX: 00000000 ESI: 00000000 EDI: f147dda4 EBP: f147ddf8 ESP: f147dd38 DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 CR0: 8005003b CR2: 00000004 CR3: 00bf3000 CR4: 00000690 Stack: 00000000 00000000 f147dda4 00000050 00000001 00000000 00000001 00000050 00000001 00000000 d3059000 00000001 00000022 000000a8 00000000 00000000 00000000 000000a1 00000000 00000000 00000001 00000000 00000000 11800000 Call Trace: [<f923564d>] __btrfs_find_all_roots+0x9d/0xf0 [btrfs] [<f9237bb1>] btrfs_qgroup_rescan_worker+0x401/0x760 [btrfs] [<f9206148>] normal_work_helper+0xc8/0x270 [btrfs] [<c025e38b>] process_one_work+0x11b/0x390 [<c025eea1>] worker_thread+0x101/0x340 [<c026432b>] kthread+0x9b/0xb0 [<c0712a71>] ret_from_kernel_thread+0x21/0x30 [<c0264290>] kthread_create_on_node+0x110/0x110 This indicates a NULL corruption in prefs_delayed list. The further investigation and bisection pointed that the call of ulist_add_merge() results in the corruption. ulist_add_merge() takes u64 as aux and writes a 64bit value into old_aux. The callers of this function in backref.c, however, pass a pointer of a pointer to old_aux. That is, the function overwrites 64bit value on 32bit pointer. This caused a NULL in the adjacent variable, in this case, prefs_delayed. Here is a quick attempt to band-aid over this: a new function, ulist_add_merge_ptr() is introduced to pass/store properly a pointer value instead of u64. There are still ugly void ** cast remaining in the callers because void ** cannot be taken implicitly. But, it's safer than explicit cast to u64, anyway. Bugzilla: https://bugzilla.novell.com/show_bug.cgi?id=887046 Cc: <stable@vger.kernel.org> [v3.11+] Signed-off-by: NTakashi Iwai <tiwai@suse.de> Signed-off-by: NChris Mason <clm@fb.com>
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由 Liu Bo 提交于
When failing to allocate space for the whole compressed extent, we'll fallback to uncompressed IO, but we've forgotten to redirty the pages which belong to this compressed extent, and these 'clean' pages will simply skip 'submit' part and go to endio directly, at last we got data corruption as we write nothing. Signed-off-by: NLiu Bo <bo.li.liu@oracle.com> Tested-By: NMartin Steigerwald <martin@lichtvoll.de> Signed-off-by: NChris Mason <clm@fb.com>
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由 Mark Fasheh 提交于
ulist_add() can return '1' on sucess, which qgroup_subtree_accounting() doesn't take into account. As a result, that value can be bubbled up to callers, causing an error to be printed. Fix this by only returning the value of ulist_add() when it indicates an error. Signed-off-by: NMark Fasheh <mfasheh@suse.de> Signed-off-by: NChris Mason <clm@fb.com>
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由 Mark Fasheh 提交于
During its tree walk, btrfs_drop_snapshot() will skip any shared subtrees it encounters. This is incorrect when we have qgroups turned on as those subtrees need to have their contents accounted. In particular, the case we're concerned with is when removing our snapshot root leaves the subtree with only one root reference. In those cases we need to find the last remaining root and add each extent in the subtree to the corresponding qgroup exclusive counts. This patch implements the shared subtree walk and a new qgroup operation, BTRFS_QGROUP_OPER_SUB_SUBTREE. When an operation of this type is encountered during qgroup accounting, we search for any root references to that extent and in the case that we find only one reference left, we go ahead and do the math on it's exclusive counts. Signed-off-by: NMark Fasheh <mfasheh@suse.de> Reviewed-by: NJosef Bacik <jbacik@fb.com> Signed-off-by: NChris Mason <clm@fb.com>
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由 Filipe Manana 提交于
Before processing the extent buffer, acquire a read lock on it, so that we're safe against concurrent updates on the extent buffer. Signed-off-by: NFilipe Manana <fdmanana@suse.com> Signed-off-by: NChris Mason <clm@fb.com>
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由 Josef Bacik 提交于
Before I extended the no_quota arg to btrfs_dec/inc_ref because I didn't understand how snapshot delete was using it and assumed that we needed the quota operations there. With Mark's work this has turned out to be not the case, we _always_ need to use no_quota for btrfs_dec/inc_ref, so just drop the argument and make __btrfs_mod_ref call it's process function with no_quota set always. Thanks, Signed-off-by: NJosef Bacik <jbacik@fb.com> Signed-off-by: NChris Mason <clm@fb.com>
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由 David Sterba 提交于
This has been discussed in thread: http://thread.gmane.org/gmane.comp.file-systems.btrfs/32528 and this patch implements this proposal: http://thread.gmane.org/gmane.comp.file-systems.btrfs/32536 Works fine for "clean" raid profiles where the raid factor correction does the right job. Otherwise it's pessimistic and may show low space although there's still some left. The df nubmers are lightly wrong in case of mixed block groups, but this is not a major usecase and can be addressed later. The RAID56 numbers are wrong almost the same way as before and will be addressed separately. CC: Hugo Mills <hugo@carfax.org.uk> CC: cwillu <cwillu@cwillu.com> CC: Josef Bacik <jbacik@fb.com> Signed-off-by: NDavid Sterba <dsterba@suse.cz> Signed-off-by: NChris Mason <clm@fb.com>
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- 14 8月, 2014 3 次提交
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由 Jeff Layton 提交于
There's no need to call locks_free_lock here while still holding the i_lock. Defer that until the lock has been dropped. Acked-by: NJ. Bruce Fields <bfields@fieldses.org> Signed-off-by: NJeff Layton <jlayton@primarydata.com>
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由 Jeff Layton 提交于
In commit 72f98e72 (locks: turn lock_flocks into a spinlock), we moved from using the BKL to a global spinlock. With this change, we lost the ability to block in the fl_release_private operation. This is problematic for NFS (and probably some other filesystems as well). Add a new list_head argument to locks_delete_lock. If that argument is non-NULL, then queue any locks that we want to free to the list instead of freeing them. Then, add a new locks_dispose_list function that will walk such a list and call locks_free_lock on them after the i_lock has been dropped. Finally, change all of the callers of locks_delete_lock to pass in a list_head, except for lease_modify. That function can be called long after the i_lock has been acquired. Deferring the freeing of a lease after unlocking it in that function is non-trivial until we overhaul some of the spinlocking in the lease code. Currently though, no filesystem that sets fl_release_private supports leases, so this is not currently a problem. We'll eventually want to make the same change in the lease code, but it needs a lot more work before we can reasonably do so. Acked-by: NJ. Bruce Fields <bfields@fieldses.org> Signed-off-by: NJeff Layton <jlayton@primarydata.com>
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由 Jeff Layton 提交于
Currently in the case where a new file lock completely replaces the old one, we end up overwriting the existing lock with the new info. This means that we have to call fl_release_private inside i_lock. Change the code to instead copy the info to new_fl, insert that lock into the correct spot and then delete the old lock. In a later patch, we'll defer the freeing of the old lock until after the i_lock has been dropped. Acked-by: NJ. Bruce Fields <bfields@fieldses.org> Signed-off-by: NJeff Layton <jlayton@primarydata.com>
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- 12 8月, 2014 4 次提交
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由 Jan Kara 提交于
If do_journal_release() races with do_journal_end() which requeues delayed works for transaction flushing, we can leave work items for flushing outstanding transactions queued while freeing them. That results in use after free and possible crash in run_timers_softirq(). Fix the problem by not requeueing works if superblock is being shut down (MS_ACTIVE not set) and using cancel_delayed_work_sync() in do_journal_release(). CC: stable@vger.kernel.org Signed-off-by: NJan Kara <jack@suse.cz>
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由 Jeff Layton 提交于
All callers of locks_copy_lock pass in a brand new file_lock struct, so there's no need to call locks_release_private on it. Replace that with a warning that fires in the event that we receive a target lock that doesn't look like it's properly initialized. Acked-by: NJ. Bruce Fields <bfields@fieldses.org> Signed-off-by: NJeff Layton <jlayton@primarydata.com>
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由 Jeff Layton 提交于
Now that they are a distinct lease type, show them as such. Cc: J. Bruce Fields <bfields@fieldses.org> Signed-off-by: NJeff Layton <jlayton@primarydata.com>
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由 Al Viro 提交于
Since 3.14 we had copy_tree() get the shadowing wrong - if we had one vfsmount shadowing another (i.e. if A is a slave of B, C is mounted on A/foo, then D got mounted on B/foo creating D' on A/foo shadowed by C), copy_tree() of A would make a copy of D' shadow the the copy of C, not the other way around. It's easy to fix, fortunately - just make sure that mount follows the one that shadows it in mnt_child as well as in mnt_hash, and when copy_tree() decides to attach a new mount, check if the last child it has added to the same parent should be shadowing the new one. And if it should, just use the same logics commit_tree() has - put the new mount into the hash and children lists right after the one that should shadow it. Cc: stable@vger.kernel.org [3.14 and later] Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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- 11 8月, 2014 1 次提交
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由 Linus Torvalds 提交于
Revert "proc: Point /proc/{mounts,net} at /proc/thread-self/{mounts,net} instead of /proc/self/{mounts,net}" This reverts commits 344470ca and e8132440. It turns out that the exact path in the symlink matters, if for somewhat unfortunate reasons: some apparmor configurations don't allow dhclient access to the per-thread /proc files. As reported by Jörg Otte: audit: type=1400 audit(1407684227.003:28): apparmor="DENIED" operation="open" profile="/sbin/dhclient" name="/proc/1540/task/1540/net/dev" pid=1540 comm="dhclient" requested_mask="r" denied_mask="r" fsuid=0 ouid=0 so we had better revert this for now. We might be able to work around this in practice by only using the per-thread symlinks if the thread isn't the thread group leader, and if the namespaces differ between threads (which basically never happens). We'll see. In the meantime, the revert was made to be intentionally easy. Reported-by: NJörg Otte <jrg.otte@gmail.com> Acked-by: NEric W. Biederman <ebiederm@xmission.com> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 09 8月, 2014 1 次提交
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由 David Herrmann 提交于
If two processes share a common memory region, they usually want some guarantees to allow safe access. This often includes: - one side cannot overwrite data while the other reads it - one side cannot shrink the buffer while the other accesses it - one side cannot grow the buffer beyond previously set boundaries If there is a trust-relationship between both parties, there is no need for policy enforcement. However, if there's no trust relationship (eg., for general-purpose IPC) sharing memory-regions is highly fragile and often not possible without local copies. Look at the following two use-cases: 1) A graphics client wants to share its rendering-buffer with a graphics-server. The memory-region is allocated by the client for read/write access and a second FD is passed to the server. While scanning out from the memory region, the server has no guarantee that the client doesn't shrink the buffer at any time, requiring rather cumbersome SIGBUS handling. 2) A process wants to perform an RPC on another process. To avoid huge bandwidth consumption, zero-copy is preferred. After a message is assembled in-memory and a FD is passed to the remote side, both sides want to be sure that neither modifies this shared copy, anymore. The source may have put sensible data into the message without a separate copy and the target may want to parse the message inline, to avoid a local copy. While SIGBUS handling, POSIX mandatory locking and MAP_DENYWRITE provide ways to achieve most of this, the first one is unproportionally ugly to use in libraries and the latter two are broken/racy or even disabled due to denial of service attacks. This patch introduces the concept of SEALING. If you seal a file, a specific set of operations is blocked on that file forever. Unlike locks, seals can only be set, never removed. Hence, once you verified a specific set of seals is set, you're guaranteed that no-one can perform the blocked operations on this file, anymore. An initial set of SEALS is introduced by this patch: - SHRINK: If SEAL_SHRINK is set, the file in question cannot be reduced in size. This affects ftruncate() and open(O_TRUNC). - GROW: If SEAL_GROW is set, the file in question cannot be increased in size. This affects ftruncate(), fallocate() and write(). - WRITE: If SEAL_WRITE is set, no write operations (besides resizing) are possible. This affects fallocate(PUNCH_HOLE), mmap() and write(). - SEAL: If SEAL_SEAL is set, no further seals can be added to a file. This basically prevents the F_ADD_SEAL operation on a file and can be set to prevent others from adding further seals that you don't want. The described use-cases can easily use these seals to provide safe use without any trust-relationship: 1) The graphics server can verify that a passed file-descriptor has SEAL_SHRINK set. This allows safe scanout, while the client is allowed to increase buffer size for window-resizing on-the-fly. Concurrent writes are explicitly allowed. 2) For general-purpose IPC, both processes can verify that SEAL_SHRINK, SEAL_GROW and SEAL_WRITE are set. This guarantees that neither process can modify the data while the other side parses it. Furthermore, it guarantees that even with writable FDs passed to the peer, it cannot increase the size to hit memory-limits of the source process (in case the file-storage is accounted to the source). The new API is an extension to fcntl(), adding two new commands: F_GET_SEALS: Return a bitset describing the seals on the file. This can be called on any FD if the underlying file supports sealing. F_ADD_SEALS: Change the seals of a given file. This requires WRITE access to the file and F_SEAL_SEAL may not already be set. Furthermore, the underlying file must support sealing and there may not be any existing shared mapping of that file. Otherwise, EBADF/EPERM is returned. The given seals are _added_ to the existing set of seals on the file. You cannot remove seals again. The fcntl() handler is currently specific to shmem and disabled on all files. A file needs to explicitly support sealing for this interface to work. A separate syscall is added in a follow-up, which creates files that support sealing. There is no intention to support this on other file-systems. Semantics are unclear for non-volatile files and we lack any use-case right now. Therefore, the implementation is specific to shmem. Signed-off-by: NDavid Herrmann <dh.herrmann@gmail.com> Acked-by: NHugh Dickins <hughd@google.com> Cc: Michael Kerrisk <mtk.manpages@gmail.com> Cc: Ryan Lortie <desrt@desrt.ca> Cc: Lennart Poettering <lennart@poettering.net> Cc: Daniel Mack <zonque@gmail.com> Cc: Andy Lutomirski <luto@amacapital.net> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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