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2017-07-17VFS: Convert sb->s_flags & MS_RDONLY to sb_rdonly(sb)David Howells
Firstly by applying the following with coccinelle's spatch: @@ expression SB; @@ -SB->s_flags & MS_RDONLY +sb_rdonly(SB) to effect the conversion to sb_rdonly(sb), then by applying: @@ expression A, SB; @@ ( -(!sb_rdonly(SB)) && A +!sb_rdonly(SB) && A | -A != (sb_rdonly(SB)) +A != sb_rdonly(SB) | -A == (sb_rdonly(SB)) +A == sb_rdonly(SB) | -!(sb_rdonly(SB)) +!sb_rdonly(SB) | -A && (sb_rdonly(SB)) +A && sb_rdonly(SB) | -A || (sb_rdonly(SB)) +A || sb_rdonly(SB) | -(sb_rdonly(SB)) != A +sb_rdonly(SB) != A | -(sb_rdonly(SB)) == A +sb_rdonly(SB) == A | -(sb_rdonly(SB)) && A +sb_rdonly(SB) && A | -(sb_rdonly(SB)) || A +sb_rdonly(SB) || A ) @@ expression A, B, SB; @@ ( -(sb_rdonly(SB)) ? 1 : 0 +sb_rdonly(SB) | -(sb_rdonly(SB)) ? A : B +sb_rdonly(SB) ? A : B ) to remove left over excess bracketage and finally by applying: @@ expression A, SB; @@ ( -(A & MS_RDONLY) != sb_rdonly(SB) +(bool)(A & MS_RDONLY) != sb_rdonly(SB) | -(A & MS_RDONLY) == sb_rdonly(SB) +(bool)(A & MS_RDONLY) == sb_rdonly(SB) ) to make comparisons against the result of sb_rdonly() (which is a bool) work correctly. Signed-off-by: David Howells <dhowells@redhat.com>
2017-06-20sched/wait: Disambiguate wq_entry->task_list and wq_head->task_list namingIngo Molnar
So I've noticed a number of instances where it was not obvious from the code whether ->task_list was for a wait-queue head or a wait-queue entry. Furthermore, there's a number of wait-queue users where the lists are not for 'tasks' but other entities (poll tables, etc.), in which case the 'task_list' name is actively confusing. To clear this all up, name the wait-queue head and entry list structure fields unambiguously: struct wait_queue_head::task_list => ::head struct wait_queue_entry::task_list => ::entry For example, this code: rqw->wait.task_list.next != &wait->task_list ... is was pretty unclear (to me) what it's doing, while now it's written this way: rqw->wait.head.next != &wait->entry ... which makes it pretty clear that we are iterating a list until we see the head. Other examples are: list_for_each_entry_safe(pos, next, &x->task_list, task_list) { list_for_each_entry(wq, &fence->wait.task_list, task_list) { ... where it's unclear (to me) what we are iterating, and during review it's hard to tell whether it's trying to walk a wait-queue entry (which would be a bug), while now it's written as: list_for_each_entry_safe(pos, next, &x->head, entry) { list_for_each_entry(wq, &fence->wait.head, entry) { Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-06-20sched/wait: Split out the wait_bit*() APIs from <linux/wait.h> into ↵Ingo Molnar
<linux/wait_bit.h> The wait_bit*() types and APIs are mixed into wait.h, but they are a pretty orthogonal extension of wait-queues. Furthermore, only about 50 kernel files use these APIs, while over 1000 use the regular wait-queue functionality. So clean up the main wait.h by moving the wait-bit functionality out of it, into a separate .h and .c file: include/linux/wait_bit.h for types and APIs kernel/sched/wait_bit.c for the implementation Update all header dependencies. This reduces the size of wait.h rather significantly, by about 30%. Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-06-20sched/wait: Rename wait_queue_t => wait_queue_entry_tIngo Molnar
Rename: wait_queue_t => wait_queue_entry_t 'wait_queue_t' was always a slight misnomer: its name implies that it's a "queue", but in reality it's a queue *entry*. The 'real' queue is the wait queue head, which had to carry the name. Start sorting this out by renaming it to 'wait_queue_entry_t'. This also allows the real structure name 'struct __wait_queue' to lose its double underscore and become 'struct wait_queue_entry', which is the more canonical nomenclature for such data types. Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-02sched/headers: Prepare to remove <linux/cred.h> inclusion from <linux/sched.h>Ingo Molnar
Add #include <linux/cred.h> dependencies to all .c files rely on sched.h doing that for them. Note that even if the count where we need to add extra headers seems high, it's still a net win, because <linux/sched.h> is included in over 2,200 files ... Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-10-10Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull more vfs updates from Al Viro: ">rename2() work from Miklos + current_time() from Deepa" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: fs: Replace current_fs_time() with current_time() fs: Replace CURRENT_TIME_SEC with current_time() for inode timestamps fs: Replace CURRENT_TIME with current_time() for inode timestamps fs: proc: Delete inode time initializations in proc_alloc_inode() vfs: Add current_time() api vfs: add note about i_op->rename changes to porting fs: rename "rename2" i_op to "rename" vfs: remove unused i_op->rename fs: make remaining filesystems use .rename2 libfs: support RENAME_NOREPLACE in simple_rename() fs: support RENAME_NOREPLACE for local filesystems ncpfs: fix unused variable warning
2016-10-10Merge branch 'work.xattr' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull vfs xattr updates from Al Viro: "xattr stuff from Andreas This completes the switch to xattr_handler ->get()/->set() from ->getxattr/->setxattr/->removexattr" * 'work.xattr' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: vfs: Remove {get,set,remove}xattr inode operations xattr: Stop calling {get,set,remove}xattr inode operations vfs: Check for the IOP_XATTR flag in listxattr xattr: Add __vfs_{get,set,remove}xattr helpers libfs: Use IOP_XATTR flag for empty directory handling vfs: Use IOP_XATTR flag for bad-inode handling vfs: Add IOP_XATTR inode operations flag vfs: Move xattr_resolve_name to the front of fs/xattr.c ecryptfs: Switch to generic xattr handlers sockfs: Get rid of getxattr iop sockfs: getxattr: Fail with -EOPNOTSUPP for invalid attribute names kernfs: Switch to generic xattr handlers hfs: Switch to generic xattr handlers jffs2: Remove jffs2_{get,set,remove}xattr macros xattr: Remove unnecessary NULL attribute name check
2016-10-07xattr: Add __vfs_{get,set,remove}xattr helpersAndreas Gruenbacher
Right now, various places in the kernel check for the existence of getxattr, setxattr, and removexattr inode operations and directly call those operations. Switch to helper functions and test for the IOP_XATTR flag instead. Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com> Acked-by: James Morris <james.l.morris@oracle.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-09-27cachefiles: Fix attempt to read i_blocks after deleting file [ver #2]David Howells
An NULL-pointer dereference happens in cachefiles_mark_object_inactive() when it tries to read i_blocks so that it can tell the cachefilesd daemon how much space it's making available. The problem is that cachefiles_drop_object() calls cachefiles_mark_object_inactive() after calling cachefiles_delete_object() because the object being marked active staves off attempts to (re-)use the file at that filename until after it has been deleted. This means that d_inode is NULL by the time we come to try to access it. To fix the problem, have the caller of cachefiles_mark_object_inactive() supply the number of blocks freed up. Without this, the following oops may occur: BUG: unable to handle kernel NULL pointer dereference at 0000000000000098 IP: [<ffffffffa06c5cc1>] cachefiles_mark_object_inactive+0x61/0xb0 [cachefiles] ... CPU: 11 PID: 527 Comm: kworker/u64:4 Tainted: G I ------------ 3.10.0-470.el7.x86_64 #1 Hardware name: Hewlett-Packard HP Z600 Workstation/0B54h, BIOS 786G4 v03.19 03/11/2011 Workqueue: fscache_object fscache_object_work_func [fscache] task: ffff880035edaf10 ti: ffff8800b77c0000 task.ti: ffff8800b77c0000 RIP: 0010:[<ffffffffa06c5cc1>] cachefiles_mark_object_inactive+0x61/0xb0 [cachefiles] RSP: 0018:ffff8800b77c3d70 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffff8800bf6cc400 RCX: 0000000000000034 RDX: 0000000000000000 RSI: ffff880090ffc710 RDI: ffff8800bf761ef8 RBP: ffff8800b77c3d88 R08: 2000000000000000 R09: 0090ffc710000000 R10: ff51005d2ff1c400 R11: 0000000000000000 R12: ffff880090ffc600 R13: ffff8800bf6cc520 R14: ffff8800bf6cc400 R15: ffff8800bf6cc498 FS: 0000000000000000(0000) GS:ffff8800bb8c0000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b CR2: 0000000000000098 CR3: 00000000019ba000 CR4: 00000000000007e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Stack: ffff880090ffc600 ffff8800bf6cc400 ffff8800867df140 ffff8800b77c3db0 ffffffffa06c48cb ffff880090ffc600 ffff880090ffc180 ffff880090ffc658 ffff8800b77c3df0 ffffffffa085d846 ffff8800a96b8150 ffff880090ffc600 Call Trace: [<ffffffffa06c48cb>] cachefiles_drop_object+0x6b/0xf0 [cachefiles] [<ffffffffa085d846>] fscache_drop_object+0xd6/0x1e0 [fscache] [<ffffffffa085d615>] fscache_object_work_func+0xa5/0x200 [fscache] [<ffffffff810a605b>] process_one_work+0x17b/0x470 [<ffffffff810a6e96>] worker_thread+0x126/0x410 [<ffffffff810a6d70>] ? rescuer_thread+0x460/0x460 [<ffffffff810ae64f>] kthread+0xcf/0xe0 [<ffffffff810ae580>] ? kthread_create_on_node+0x140/0x140 [<ffffffff81695418>] ret_from_fork+0x58/0x90 [<ffffffff810ae580>] ? kthread_create_on_node+0x140/0x140 The oopsing code shows: callq 0xffffffff810af6a0 <wake_up_bit> mov 0xf8(%r12),%rax mov 0x30(%rax),%rax mov 0x98(%rax),%rax <---- oops here lock add %rax,0x130(%rbx) where this is: d_backing_inode(object->dentry)->i_blocks Fixes: a5b3a80b899bda0f456f1246c4c5a1191ea01519 (CacheFiles: Provide read-and-reset release counters for cachefilesd) Reported-by: Jianhong Yin <jiyin@redhat.com> Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@redhat.com> Reviewed-by: Steve Dickson <steved@redhat.com> cc: stable@vger.kernel.org Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-09-27fs: rename "rename2" i_op to "rename"Miklos Szeredi
Generated patch: sed -i "s/\.rename2\t/\.rename\t\t/" `git grep -wl rename2` sed -i "s/\brename2\b/rename/g" `git grep -wl rename2` Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2016-09-27vfs: remove unused i_op->renameMiklos Szeredi
No in-tree uses remain. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2016-08-03cachefiles: Fix race between inactivating and culling a cache objectDavid Howells
There's a race between cachefiles_mark_object_inactive() and cachefiles_cull(): (1) cachefiles_cull() can't delete a backing file until the cache object is marked inactive, but as soon as that's the case it's fair game. (2) cachefiles_mark_object_inactive() marks the object as being inactive and *only then* reads the i_blocks on the backing inode - but cachefiles_cull() might've managed to delete it by this point. Fix this by making sure cachefiles_mark_object_inactive() gets any data it needs from the backing inode before deactivating the object. Without this, the following oops may occur: BUG: unable to handle kernel NULL pointer dereference at 0000000000000098 IP: [<ffffffffa06c5cc1>] cachefiles_mark_object_inactive+0x61/0xb0 [cachefiles] ... CPU: 11 PID: 527 Comm: kworker/u64:4 Tainted: G I ------------ 3.10.0-470.el7.x86_64 #1 Hardware name: Hewlett-Packard HP Z600 Workstation/0B54h, BIOS 786G4 v03.19 03/11/2011 Workqueue: fscache_object fscache_object_work_func [fscache] task: ffff880035edaf10 ti: ffff8800b77c0000 task.ti: ffff8800b77c0000 RIP: 0010:[<ffffffffa06c5cc1>] cachefiles_mark_object_inactive+0x61/0xb0 [cachefiles] RSP: 0018:ffff8800b77c3d70 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffff8800bf6cc400 RCX: 0000000000000034 RDX: 0000000000000000 RSI: ffff880090ffc710 RDI: ffff8800bf761ef8 RBP: ffff8800b77c3d88 R08: 2000000000000000 R09: 0090ffc710000000 R10: ff51005d2ff1c400 R11: 0000000000000000 R12: ffff880090ffc600 R13: ffff8800bf6cc520 R14: ffff8800bf6cc400 R15: ffff8800bf6cc498 FS: 0000000000000000(0000) GS:ffff8800bb8c0000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b CR2: 0000000000000098 CR3: 00000000019ba000 CR4: 00000000000007e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Stack: ffff880090ffc600 ffff8800bf6cc400 ffff8800867df140 ffff8800b77c3db0 ffffffffa06c48cb ffff880090ffc600 ffff880090ffc180 ffff880090ffc658 ffff8800b77c3df0 ffffffffa085d846 ffff8800a96b8150 ffff880090ffc600 Call Trace: [<ffffffffa06c48cb>] cachefiles_drop_object+0x6b/0xf0 [cachefiles] [<ffffffffa085d846>] fscache_drop_object+0xd6/0x1e0 [fscache] [<ffffffffa085d615>] fscache_object_work_func+0xa5/0x200 [fscache] [<ffffffff810a605b>] process_one_work+0x17b/0x470 [<ffffffff810a6e96>] worker_thread+0x126/0x410 [<ffffffff810a6d70>] ? rescuer_thread+0x460/0x460 [<ffffffff810ae64f>] kthread+0xcf/0xe0 [<ffffffff810ae580>] ? kthread_create_on_node+0x140/0x140 [<ffffffff81695418>] ret_from_fork+0x58/0x90 [<ffffffff810ae580>] ? kthread_create_on_node+0x140/0x140 The oopsing code shows: callq 0xffffffff810af6a0 <wake_up_bit> mov 0xf8(%r12),%rax mov 0x30(%rax),%rax mov 0x98(%rax),%rax <---- oops here lock add %rax,0x130(%rbx) where this is: d_backing_inode(object->dentry)->i_blocks Fixes: a5b3a80b899bda0f456f1246c4c5a1191ea01519 (CacheFiles: Provide read-and-reset release counters for cachefilesd) Reported-by: Jianhong Yin <jiyin@redhat.com> Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@redhat.com> Reviewed-by: Steve Dickson <steved@redhat.com> cc: stable@vger.kernel.org Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-06-30Merge branch 'd_real' of ↵Al Viro
git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs into work.misc
2016-06-01FS-Cache: make check_consistency callback return intYan, Zheng
__fscache_check_consistency() calls check_consistency() callback and return the callback's return value. But the return type of check_consistency() is bool. So __fscache_check_consistency() return 1 if the cache is inconsistent. This is inconsistent with the document. Signed-off-by: Yan, Zheng <zyan@redhat.com> Acked-by: David Howells <dhowells@redhat.com>
2016-05-29drop redundant ->owner initializationsAl Viro
it's not needed for file_operations of inodes located on fs defined in the hosting module and for file_operations that go into procfs. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-04-04mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macrosKirill A. Shutemov
PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago with promise that one day it will be possible to implement page cache with bigger chunks than PAGE_SIZE. This promise never materialized. And unlikely will. We have many places where PAGE_CACHE_SIZE assumed to be equal to PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_* or PAGE_* constant should be used in a particular case, especially on the border between fs and mm. Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much breakage to be doable. Let's stop pretending that pages in page cache are special. They are not. The changes are pretty straight-forward: - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN}; - page_cache_get() -> get_page(); - page_cache_release() -> put_page(); This patch contains automated changes generated with coccinelle using script below. For some reason, coccinelle doesn't patch header files. I've called spatch for them manually. The only adjustment after coccinelle is revert of changes to PAGE_CAHCE_ALIGN definition: we are going to drop it later. There are few places in the code where coccinelle didn't reach. I'll fix them manually in a separate patch. Comments and documentation also will be addressed with the separate patch. virtual patch @@ expression E; @@ - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ expression E; @@ - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ @@ - PAGE_CACHE_SHIFT + PAGE_SHIFT @@ @@ - PAGE_CACHE_SIZE + PAGE_SIZE @@ @@ - PAGE_CACHE_MASK + PAGE_MASK @@ expression E; @@ - PAGE_CACHE_ALIGN(E) + PAGE_ALIGN(E) @@ expression E; @@ - page_cache_get(E) + get_page(E) @@ expression E; @@ - page_cache_release(E) + put_page(E) Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-02-01CacheFiles: Provide read-and-reset release counters for cachefilesdDavid Howells
Provide read-and-reset objects- and blocks-released counters for cachefilesd to use to work out whether there's anything new that can be culled. One of the problems cachefilesd has is that if all the objects in the cache are pinned by inodes lying dormant in the kernel inode cache, there isn't anything for it to cull. In such a case, it just spins around walking the filesystem tree and scanning for something to cull. This eats up a lot of CPU time. By telling cachefilesd if there have been any releases, the daemon can sleep until there is the possibility of something to do. cachefilesd finds this information by the following means: (1) When the control fd is read, the kernel presents a list of values of interest. "freleased=N" and "breleased=N" are added to this list to indicate the number of files released and number of blocks released since the last read call. At this point the counters are reset. (2) POLLIN is signalled if the number of files released becomes greater than 0. Note that by 'released' it just means that the kernel has released its interest in those files for the moment, not necessarily that the files should be deleted from the cache. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Steve Dickson <steved@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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>
2016-01-04convert a bunch of open-coded instances of memdup_user_nul()Al Viro
A _lot_ of ->write() instances were open-coding it; some are converted to memdup_user_nul(), a lot more remain... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-11-16FS-Cache: Add missing initialization of ret in cachefiles_write_page()Geert Uytterhoeven
fs/cachefiles/rdwr.c: In function ‘cachefiles_write_page’: fs/cachefiles/rdwr.c:882: warning: ‘ret’ may be used uninitialized in this function If the jump to label "error" is taken, "ret" will indeed be uninitialized, and random stack data may be printed by the debug code. Fixes: 102f4d900c9c8f5e ("FS-Cache: Handle a write to the page immediately beyond the EOF marker") Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-11-11FS-Cache: Handle a write to the page immediately beyond the EOF markerDavid Howells
Handle a write being requested to the page immediately beyond the EOF marker on a cache object. Currently this gets an assertion failure in CacheFiles because the EOF marker is used there to encode information about a partial page at the EOF - which could lead to an unknown blank spot in the file if we extend the file over it. The problem is actually in fscache where we check the index of the page being written against store_limit. store_limit is set to the number of pages that we're allowed to store by fscache_set_store_limit() - which means it's one more than the index of the last page we're allowed to store. The problem is that we permit writing to a page with an index _equal_ to the store limit - when we should reject that case. Whilst we're at it, change the triggered assertion in CacheFiles to just return -ENOBUFS instead. The assertion failure looks something like this: CacheFiles: Assertion failed 1000 < 7b1 is false ------------[ cut here ]------------ kernel BUG at fs/cachefiles/rdwr.c:962! ... RIP: 0010:[<ffffffffa02c9e83>] [<ffffffffa02c9e83>] cachefiles_write_page+0x273/0x2d0 [cachefiles] Cc: stable@vger.kernel.org # v2.6.31+; earlier - that + backport of a17754f (at least) Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-11-11cachefiles: perform test on s_blocksize when opening cache file.NeilBrown
cachefiles requires that s_blocksize in the cache is not greater than PAGE_SIZE, and performs the check every time a block is accessed. Move the test to the place where the file is "opened", where other file-validity tests are performed. Signed-off-by: NeilBrown <neilb@suse.de> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-11-06mm, page_alloc: rename __GFP_WAIT to __GFP_RECLAIMMel Gorman
__GFP_WAIT was used to signal that the caller was in atomic context and could not sleep. Now it is possible to distinguish between true atomic context and callers that are not willing to sleep. The latter should clear __GFP_DIRECT_RECLAIM so kswapd will still wake. As clearing __GFP_WAIT behaves differently, there is a risk that people will clear the wrong flags. This patch renames __GFP_WAIT to __GFP_RECLAIM to clearly indicate what it does -- setting it allows all reclaim activity, clearing them prevents it. [akpm@linux-foundation.org: fix build] [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Christoph Lameter <cl@linux.com> Acked-by: David Rientjes <rientjes@google.com> Cc: Vitaly Wool <vitalywool@gmail.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-23Merge branch 'fscache-fixes' into for-nextAl Viro
2015-04-15VFS: fs/cachefiles: d_backing_inode() annotationsDavid Howells
Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-04-15VFS: Cachefiles should perform fs modifications on the top layer onlyDavid Howells
Cachefiles should perform fs modifications (eg. vfs_unlink()) on the top layer only and should not attempt to alter the lower layer. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-02-24FS-Cache: Count culled objects and objects rejected due to lack of spaceDavid Howells
Count the number of objects that get culled by the cache backend and the number of objects that the cache backend declines to instantiate due to lack of space in the cache. These numbers are made available through /proc/fs/fscache/stats Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Steve Dickson <steved@redhat.com> Acked-by: Jeff Layton <jeff.layton@primarydata.com>
2015-02-22Cachefiles: Fix up scripted S_ISDIR/S_ISREG/S_ISLNK conversionsDavid Howells
Fix up the following scripted S_ISDIR/S_ISREG/S_ISLNK conversions (or lack thereof) in cachefiles: (1) Cachefiles mostly wants to use d_can_lookup() rather than d_is_dir() as it doesn't want to deal with automounts in its cache. (2) Coccinelle didn't find S_IS* expressions in ASSERT() statements in cachefiles. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-02-22VFS: (Scripted) Convert S_ISLNK/DIR/REG(dentry->d_inode) to d_is_*(dentry)David Howells
Convert the following where appropriate: (1) S_ISLNK(dentry->d_inode) to d_is_symlink(dentry). (2) S_ISREG(dentry->d_inode) to d_is_reg(dentry). (3) S_ISDIR(dentry->d_inode) to d_is_dir(dentry). This is actually more complicated than it appears as some calls should be converted to d_can_lookup() instead. The difference is whether the directory in question is a real dir with a ->lookup op or whether it's a fake dir with a ->d_automount op. In some circumstances, we can subsume checks for dentry->d_inode not being NULL into this, provided we the code isn't in a filesystem that expects d_inode to be NULL if the dirent really *is* negative (ie. if we're going to use d_inode() rather than d_backing_inode() to get the inode pointer). Note that the dentry type field may be set to something other than DCACHE_MISS_TYPE when d_inode is NULL in the case of unionmount, where the VFS manages the fall-through from a negative dentry to a lower layer. In such a case, the dentry type of the negative union dentry is set to the same as the type of the lower dentry. However, if you know d_inode is not NULL at the call site, then you can use the d_is_xxx() functions even in a filesystem. There is one further complication: a 0,0 chardev dentry may be labelled DCACHE_WHITEOUT_TYPE rather than DCACHE_SPECIAL_TYPE. Strictly, this was intended for special directory entry types that don't have attached inodes. The following perl+coccinelle script was used: use strict; my @callers; open($fd, 'git grep -l \'S_IS[A-Z].*->d_inode\' |') || die "Can't grep for S_ISDIR and co. callers"; @callers = <$fd>; close($fd); unless (@callers) { print "No matches\n"; exit(0); } my @cocci = ( '@@', 'expression E;', '@@', '', '- S_ISLNK(E->d_inode->i_mode)', '+ d_is_symlink(E)', '', '@@', 'expression E;', '@@', '', '- S_ISDIR(E->d_inode->i_mode)', '+ d_is_dir(E)', '', '@@', 'expression E;', '@@', '', '- S_ISREG(E->d_inode->i_mode)', '+ d_is_reg(E)' ); my $coccifile = "tmp.sp.cocci"; open($fd, ">$coccifile") || die $coccifile; print($fd "$_\n") || die $coccifile foreach (@cocci); close($fd); foreach my $file (@callers) { chomp $file; print "Processing ", $file, "\n"; system("spatch", "--sp-file", $coccifile, $file, "--in-place", "--no-show-diff") == 0 || die "spatch failed"; } [AV: overlayfs parts skipped] Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2014-11-19assorted conversions to %p[dD]Al Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2014-10-14Merge tag 'fscache-fixes-20141013' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs Pull fs-cache fixes from David Howells: "Two fixes for bugs in CacheFiles and a cleanup in FS-Cache" * tag 'fscache-fixes-20141013' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs: fs/fscache/object-list.c: use __seq_open_private() CacheFiles: Fix incorrect test for in-memory object collision CacheFiles: Handle object being killed before being set up
2014-10-13CacheFiles: Fix incorrect test for in-memory object collisionDavid Howells
When CacheFiles cache objects are in use, they have in-memory representations, as defined by the cachefiles_object struct. These are kept in a tree rooted in the cache and indexed by dentry pointer (since there's a unique mapping between object index key and dentry). Collisions can occur between a representation already in the tree and a new representation being set up because it takes time to dispose of an old representation - particularly if it must be unlinked or renamed. When such a collision occurs, cachefiles_mark_object_active() is meant to check to see if the old, already-present representation is in the process of being discarded (ie. FSCACHE_OBJECT_IS_LIVE is not set on it) - and, if so, wait for the representation to be removed (ie. CACHEFILES_OBJECT_ACTIVE is then cleared). However, the test for whether the old representation is still live is checking the new object - which always will be live at this point. This leads to an oops looking like: CacheFiles: Error: Unexpected object collision object: OBJ1b354 objstate=LOOK_UP_OBJECT fl=8 wbusy=2 ev=0[0] ops=0 inp=0 exc=0 parent=ffff88053f5417c0 cookie=ffff880538f202a0 [pr=ffff8805381b7160 nd=ffff880509c6eb78 fl=27] key=[8] '2490000000000000' xobject: OBJ1a600 xobjstate=DROP_OBJECT fl=70 wbusy=2 ev=0[0] xops=0 inp=0 exc=0 xparent=ffff88053f5417c0 xcookie=ffff88050f4cbf70 [pr=ffff8805381b7160 nd= (null) fl=12] ------------[ cut here ]------------ kernel BUG at fs/cachefiles/namei.c:200! ... Workqueue: fscache_object fscache_object_work_func [fscache] ... RIP: ... cachefiles_walk_to_object+0x7ea/0x860 [cachefiles] ... Call Trace: [<ffffffffa04dadd8>] ? cachefiles_lookup_object+0x58/0x100 [cachefiles] [<ffffffffa01affe9>] ? fscache_look_up_object+0xb9/0x1d0 [fscache] [<ffffffffa01afc4d>] ? fscache_parent_ready+0x2d/0x80 [fscache] [<ffffffffa01b0672>] ? fscache_object_work_func+0x92/0x1f0 [fscache] [<ffffffff8107e82b>] ? process_one_work+0x16b/0x400 [<ffffffff8107fc16>] ? worker_thread+0x116/0x380 [<ffffffff8107fb00>] ? manage_workers.isra.21+0x290/0x290 [<ffffffff81085edc>] ? kthread+0xbc/0xe0 [<ffffffff81085e20>] ? flush_kthread_worker+0x80/0x80 [<ffffffff81502d0c>] ? ret_from_fork+0x7c/0xb0 [<ffffffff81085e20>] ? flush_kthread_worker+0x80/0x80 Reported-by: Manuel Schölling <manuel.schoelling@gmx.de> Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Steve Dickson <steved@redhat.com>
2014-10-09cachefiles_write_page(): switch to __kernel_write()Al Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2014-09-30CacheFiles: Handle object being killed before being set upDavid Howells
If a cache object gets killed whilst in the process of being set up - for instance if the netfs relinquishes the cookie that the object is associated with - then the object's state machine will transit to the DROP_OBJECT state without necessarily going through the LOOKUP_OBJECT or CREATE_OBJECT states. This is a problem for CacheFiles because cachefiles_drop_object() assumes that object->dentry will be set upon reaching the DROP_OBJECT state and has an ASSERT() to that effect (see the oops below) - but object->dentry doesn't get set until the LOOKUP_OBJECT or CREATE_OBJECT states (and not always then if they fail). To fix this, just make the dentry cleanup in cachefiles_drop_object() conditional on the dentry actually being set and remove the assertion. CacheFiles: Assertion failed ------------[ cut here ]------------ kernel BUG at .../fs/cachefiles/namei.c:425! ... Workqueue: fscache_object fscache_object_work_func [fscache] ... RIP: ... cachefiles_delete_object+0xcd/0x110 [cachefiles] ... Call Trace: [<ffffffffa043280f>] ? cachefiles_drop_object+0xff/0x130 [cachefiles] [<ffffffffa02ac511>] ? fscache_drop_object+0xd1/0x1d0 [fscache] [<ffffffffa02ac697>] ? fscache_object_work_func+0x87/0x210 [fscache] [<ffffffff81080635>] ? process_one_work+0x155/0x450 [<ffffffff81081c44>] ? worker_thread+0x114/0x370 [<ffffffff81081b30>] ? manage_workers.isra.21+0x2c0/0x2c0 [<ffffffff81087fcc>] ? kthread+0xbc/0xe0 [<ffffffff81087f10>] ? flush_kthread_worker+0xa0/0xa0 [<ffffffff8150638c>] ? ret_from_fork+0x7c/0xb0 [<ffffffff81087f10>] ? flush_kthread_worker+0xa0/0xa0 Reported-by: Manuel Schölling <manuel.schoelling@gmx.de> Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Steve Dickson <steved@redhat.com>
2014-09-26fs/cachefiles: add missing \n to kerror conversionsFabian Frederick
Commit 0227d6abb378 ("fs/cachefiles: replace kerror by pr_err") didn't include newline featuring in original kerror definition Signed-off-by: Fabian Frederick <fabf@skynet.be> Reported-by: David Howells <dhowells@redhat.com> Acked-by: David Howells <dhowells@redhat.com> Cc: <stable@vger.kernel.org> [3.16.x] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-09-17CacheFiles: Handle rename2David Howells
Not all filesystems now provide the rename i_op - ext4 for one - but rather provide the rename2 i_op. CacheFiles checks that the filesystem has rename and so will reject ext4 now with EPERM: CacheFiles: Failed to register: -1 Fix this by checking for rename2 as an alternative. The call to vfs_rename() actually handles selection of the appropriate function, so we needn't worry about that. Turning on debugging shows: [cachef] ==> cachefiles_get_directory(,,cache) [cachef] subdir -> ffff88000b22b778 positive [cachef] <== cachefiles_get_directory() = -1 [check] where -1 is EPERM. Signed-off-by: David Howells <dhowells@redhat.com>
2014-09-17cachefiles: remove two unused pagevecs.NeilBrown
These two have been unused since commit c4d6d8dbf335c7fa47341654a37c53a512b519bb CacheFiles: Fix the marking of cached pages in 3.8. Signed-off-by: NeilBrown <neilb@suse.de> Signed-off-by: David Howells <dhowells@redhat.com>
2014-06-06fs/cachefiles: replace kerror by pr_errFabian Frederick
Also add pr_fmt in internal.h Signed-off-by: Fabian Frederick <fabf@skynet.be> Cc: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-06-06FS/CACHEFILES: convert printk to pr_foo()Fabian Frederick
Signed-off-by: Fabian Frederick <fabf@skynet.be> Cc: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-12Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull vfs updates from Al Viro: "The first vfs pile, with deep apologies for being very late in this window. Assorted cleanups and fixes, plus a large preparatory part of iov_iter work. There's a lot more of that, but it'll probably go into the next merge window - it *does* shape up nicely, removes a lot of boilerplate, gets rid of locking inconsistencie between aio_write and splice_write and I hope to get Kent's direct-io rewrite merged into the same queue, but some of the stuff after this point is having (mostly trivial) conflicts with the things already merged into mainline and with some I want more testing. This one passes LTP and xfstests without regressions, in addition to usual beating. BTW, readahead02 in ltp syscalls testsuite has started giving failures since "mm/readahead.c: fix readahead failure for memoryless NUMA nodes and limit readahead pages" - might be a false positive, might be a real regression..." * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (63 commits) missing bits of "splice: fix racy pipe->buffers uses" cifs: fix the race in cifs_writev() ceph_sync_{,direct_}write: fix an oops on ceph_osdc_new_request() failure kill generic_file_buffered_write() ocfs2_file_aio_write(): switch to generic_perform_write() ceph_aio_write(): switch to generic_perform_write() xfs_file_buffered_aio_write(): switch to generic_perform_write() export generic_perform_write(), start getting rid of generic_file_buffer_write() generic_file_direct_write(): get rid of ppos argument btrfs_file_aio_write(): get rid of ppos kill the 5th argument of generic_file_buffered_write() kill the 4th argument of __generic_file_aio_write() lustre: don't open-code kernel_recvmsg() ocfs2: don't open-code kernel_recvmsg() drbd: don't open-code kernel_recvmsg() constify blk_rq_map_user_iov() and friends lustre: switch to kernel_sendmsg() ocfs2: don't open-code kernel_sendmsg() take iov_iter stuff to mm/iov_iter.c process_vm_access: tidy up a bit ...
2014-04-04Merge branch 'cross-rename' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs Pull renameat2 system call from Miklos Szeredi: "This adds a new syscall, renameat2(), which is the same as renameat() but with a flags argument. The purpose of extending rename is to add cross-rename, a symmetric variant of rename, which exchanges the two files. This allows interesting things, which were not possible before, for example atomically replacing a directory tree with a symlink, etc... This also allows overlayfs and friends to operate on whiteouts atomically. Andy Lutomirski also suggested a "noreplace" flag, which disables the overwriting behavior of rename. These two flags, RENAME_EXCHANGE and RENAME_NOREPLACE are only implemented for ext4 as an example and for testing" * 'cross-rename' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs: ext4: add cross rename support ext4: rename: split out helper functions ext4: rename: move EMLINK check up ext4: rename: create ext4_renament structure for local vars vfs: add cross-rename vfs: lock_two_nondirectories: allow directory args security: add flags to rename hooks vfs: add RENAME_NOREPLACE flag vfs: add renameat2 syscall vfs: rename: use common code for dir and non-dir vfs: rename: move d_move() up vfs: add d_is_dir()
2014-04-03fs: cachefiles: use add_to_page_cache_lru()Johannes Weiner
This code used to have its own lru cache pagevec up until a0b8cab3 ("mm: remove lru parameter from __pagevec_lru_add and remove parts of pagevec API"). Now it's just add_to_page_cache() followed by lru_cache_add(), might as well use add_to_page_cache_lru() directly. Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Rik van Riel <riel@redhat.com> Reviewed-by: Minchan Kim <minchan@kernel.org> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Bob Liu <bob.liu@oracle.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Dave Chinner <david@fromorbit.com> Cc: Greg Thelen <gthelen@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jan Kara <jack@suse.cz> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Luigi Semenzato <semenzato@google.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Metin Doslu <metin@citusdata.com> Cc: Michel Lespinasse <walken@google.com> Cc: Ozgun Erdogan <ozgun@citusdata.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Roman Gushchin <klamm@yandex-team.ru> Cc: Ryan Mallon <rmallon@gmail.com> Cc: Tejun Heo <tj@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-01get rid of pointless checks for NULL ->i_opAl Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2014-04-01security: add flags to rename hooksMiklos Szeredi
Add flags to security_path_rename() and security_inode_rename() hooks. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Reviewed-by: J. Bruce Fields <bfields@redhat.com>
2014-04-01vfs: add renameat2 syscallMiklos Szeredi
Add new renameat2 syscall, which is the same as renameat with an added flags argument. Pass flags to vfs_rename() and to i_op->rename() as well. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Reviewed-by: J. Bruce Fields <bfields@redhat.com>
2013-11-13Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull vfs updates from Al Viro: "All kinds of stuff this time around; some more notable parts: - RCU'd vfsmounts handling - new primitives for coredump handling - files_lock is gone - Bruce's delegations handling series - exportfs fixes plus misc stuff all over the place" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (101 commits) ecryptfs: ->f_op is never NULL locks: break delegations on any attribute modification locks: break delegations on link locks: break delegations on rename locks: helper functions for delegation breaking locks: break delegations on unlink namei: minor vfs_unlink cleanup locks: implement delegations locks: introduce new FL_DELEG lock flag vfs: take i_mutex on renamed file vfs: rename I_MUTEX_QUOTA now that it's not used for quotas vfs: don't use PARENT/CHILD lock classes for non-directories vfs: pull ext4's double-i_mutex-locking into common code exportfs: fix quadratic behavior in filehandle lookup exportfs: better variable name exportfs: move most of reconnect_path to helper function exportfs: eliminate unused "noprogress" counter exportfs: stop retrying once we race with rename/remove exportfs: clear DISCONNECTED on all parents sooner exportfs: more detailed comment for path_reconnect ...
2013-11-09locks: break delegations on any attribute modificationJ. Bruce Fields
NFSv4 uses leases to guarantee that clients can cache metadata as well as data. Cc: Mikulas Patocka <mikulas@artax.karlin.mff.cuni.cz> Cc: David Howells <dhowells@redhat.com> Cc: Tyler Hicks <tyhicks@canonical.com> Cc: Dustin Kirkland <dustin.kirkland@gazzang.com> Acked-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2013-11-09locks: break delegations on renameJ. Bruce Fields
Cc: David Howells <dhowells@redhat.com> Acked-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2013-11-09locks: break delegations on unlinkJ. Bruce Fields
We need to break delegations on any operation that changes the set of links pointing to an inode. Start with unlink. Such operations also hold the i_mutex on a parent directory. Breaking a delegation may require waiting for a timeout (by default 90 seconds) in the case of a unresponsive NFS client. To avoid blocking all directory operations, we therefore drop locks before waiting for the delegation. The logic then looks like: acquire locks ... test for delegation; if found: take reference on inode release locks wait for delegation break drop reference on inode retry It is possible this could never terminate. (Even if we take precautions to prevent another delegation being acquired on the same inode, we could get a different inode on each retry.) But this seems very unlikely. The initial test for a delegation happens after the lock on the target inode is acquired, but the directory inode may have been acquired further up the call stack. We therefore add a "struct inode **" argument to any intervening functions, which we use to pass the inode back up to the caller in the case it needs a delegation synchronously broken. Cc: David Howells <dhowells@redhat.com> Cc: Tyler Hicks <tyhicks@canonical.com> Cc: Dustin Kirkland <dustin.kirkland@gazzang.com> Acked-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2013-09-27FS-Cache: Provide the ability to enable/disable cookiesDavid Howells
Provide the ability to enable and disable fscache cookies. A disabled cookie will reject or ignore further requests to: Acquire a child cookie Invalidate and update backing objects Check the consistency of a backing object Allocate storage for backing page Read backing pages Write to backing pages but still allows: Checks/waits on the completion of already in-progress objects Uncaching of pages Relinquishment of cookies Two new operations are provided: (1) Disable a cookie: void fscache_disable_cookie(struct fscache_cookie *cookie, bool invalidate); If the cookie is not already disabled, this locks the cookie against other dis/enablement ops, marks the cookie as being disabled, discards or invalidates any backing objects and waits for cessation of activity on any associated object. This is a wrapper around a chunk split out of fscache_relinquish_cookie(), but it reinitialises the cookie such that it can be reenabled. All possible failures are handled internally. The caller should consider calling fscache_uncache_all_inode_pages() afterwards to make sure all page markings are cleared up. (2) Enable a cookie: void fscache_enable_cookie(struct fscache_cookie *cookie, bool (*can_enable)(void *data), void *data) If the cookie is not already enabled, this locks the cookie against other dis/enablement ops, invokes can_enable() and, if the cookie is not an index cookie, will begin the procedure of acquiring backing objects. The optional can_enable() function is passed the data argument and returns a ruling as to whether or not enablement should actually be permitted to begin. All possible failures are handled internally. The cookie will only be marked as enabled if provisional backing objects are allocated. A later patch will introduce these to NFS. Cookie enablement during nfs_open() is then contingent on i_writecount <= 0. can_enable() checks for a race between open(O_RDONLY) and open(O_WRONLY/O_RDWR). This simplifies NFS's cookie handling and allows us to get rid of open(O_RDONLY) accidentally introducing caching to an inode that's open for writing already. One operation has its API modified: (3) Acquire a cookie. struct fscache_cookie *fscache_acquire_cookie( struct fscache_cookie *parent, const struct fscache_cookie_def *def, void *netfs_data, bool enable); This now has an additional argument that indicates whether the requested cookie should be enabled by default. It doesn't need the can_enable() function because the caller must prevent multiple calls for the same netfs object and it doesn't need to take the enablement lock because no one else can get at the cookie before this returns. Signed-off-by: David Howells <dhowells@redhat.com
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