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2016-01-11Merge branch 'work.xattr' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull vfs xattr updates from Al Viro: "Andreas' xattr cleanup series. It's a followup to his xattr work that went in last cycle; -0.5KLoC" * 'work.xattr' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: xattr handlers: Simplify list operation ocfs2: Replace list xattr handler operations nfs: Move call to security_inode_listsecurity into nfs_listxattr xfs: Change how listxattr generates synthetic attributes tmpfs: listxattr should include POSIX ACL xattrs tmpfs: Use xattr handler infrastructure btrfs: Use xattr handler infrastructure vfs: Distinguish between full xattr names and proper prefixes posix acls: Remove duplicate xattr name definitions gfs2: Remove gfs2_xattr_acl_chmod vfs: Remove vfs_xattr_cmp
2015-12-08replace ->follow_link() with new method that could stay in RCU modeAl Viro
new method: ->get_link(); replacement of ->follow_link(). The differences are: * inode and dentry are passed separately * might be called both in RCU and non-RCU mode; the former is indicated by passing it a NULL dentry. * when called that way it isn't allowed to block and should return ERR_PTR(-ECHILD) if it needs to be called in non-RCU mode. It's a flagday change - the old method is gone, all in-tree instances converted. Conversion isn't hard; said that, so far very few instances do not immediately bail out when called in RCU mode. That'll change in the next commits. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-12-06posix acls: Remove duplicate xattr name definitionsAndreas Gruenbacher
Remove POSIX_ACL_XATTR_{ACCESS,DEFAULT} and GFS2_POSIX_ACL_{ACCESS,DEFAULT} and replace them with the definitions in <include/uapi/linux/xattr.h>. Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com> Reviewed-by: James Morris <james.l.morris@oracle.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-11-13Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client Pull Ceph updates from Sage Weil: "There are several patches from Ilya fixing RBD allocation lifecycle issues, a series adding a nocephx_sign_messages option (and associated bug fixes/cleanups), several patches from Zheng improving the (directory) fsync behavior, a big improvement in IO for direct-io requests when striping is enabled from Caifeng, and several other small fixes and cleanups" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client: libceph: clear msg->con in ceph_msg_release() only libceph: add nocephx_sign_messages option libceph: stop duplicating client fields in messenger libceph: drop authorizer check from cephx msg signing routines libceph: msg signing callouts don't need con argument libceph: evaluate osd_req_op_data() arguments only once ceph: make fsync() wait unsafe requests that created/modified inode ceph: add request to i_unsafe_dirops when getting unsafe reply libceph: introduce ceph_x_authorizer_cleanup() ceph: don't invalidate page cache when inode is no longer used rbd: remove duplicate calls to rbd_dev_mapping_clear() rbd: set device_type::release instead of device::release rbd: don't free rbd_dev outside of the release callback rbd: return -ENOMEM instead of pool id if rbd_dev_create() fails libceph: use local variable cursor instead of &msg->cursor libceph: remove con argument in handle_reply() ceph: combine as many iovec as possile into one OSD request ceph: fix message length computation ceph: fix a comment typo rbd: drop null test before destroy functions
2015-11-06mm, fs: introduce mapping_gfp_constraint()Michal Hocko
There are many places which use mapping_gfp_mask to restrict a more generic gfp mask which would be used for allocations which are not directly related to the page cache but they are performed in the same context. Let's introduce a helper function which makes the restriction explicit and easier to track. This patch doesn't introduce any functional changes. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Michal Hocko <mhocko@suse.com> Suggested-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-11-02libceph: msg signing callouts don't need con argumentIlya Dryomov
We can use msg->con instead - at the point we sign an outgoing message or check the signature on the incoming one, msg->con is always set. We wouldn't know how to sign a message without an associated session (i.e. msg->con == NULL) and being able to sign a message using an explicitly provided authorizer is of no use. Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2015-11-02ceph: make fsync() wait unsafe requests that created/modified inodeYan, Zheng
If we get a unsafe reply for request that created/modified inode, add the unsafe request to a list in the newly created/modified inode. So we can make fsync() wait these unsafe requests. Signed-off-by: Yan, Zheng <zyan@redhat.com>
2015-11-02ceph: add request to i_unsafe_dirops when getting unsafe replyYan, Zheng
Previously we add request to i_unsafe_dirops when registering request. So ceph_fsync() also waits for imcomplete requests. This is unnecessary, ceph_fsync() only needs to wait unsafe requests. Signed-off-by: Yan, Zheng <zyan@redhat.com>
2015-11-02ceph: don't invalidate page cache when inode is no longer usedYan, Zheng
ceph_check_caps() invalidate page cache when inode is not used by any open file. This behaviour is not friendly for workload that repeatly read files. Signed-off-by: Yan, Zheng <zyan@redhat.com>
2015-11-02ceph: combine as many iovec as possile into one OSD requestZhu, Caifeng
Both ceph_sync_direct_write and ceph_sync_read iterate iovec elements one by one, send one OSD request for each iovec. This is sub-optimal, We can combine serveral iovec into one page vector, and send an OSD request for the whole page vector. Signed-off-by: Zhu, Caifeng <zhucaifeng@unissoft-nj.com> Signed-off-by: Yan, Zheng <zyan@redhat.com>
2015-11-02ceph: fix message length computationArnd Bergmann
create_request_message() computes the maximum length of a message, but uses the wrong type for the time stamp: sizeof(struct timespec) may be 8 or 16 depending on the architecture, while sizeof(struct ceph_timespec) is always 8, and that is what gets put into the message. Found while auditing the uses of timespec for y2038 problems. Fixes: b8e69066d8af ("ceph: include time stamp in every MDS request") Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Yan, Zheng <zyan@redhat.com>
2015-11-02ceph: fix a comment typoGeliang Tang
Signed-off-by: Geliang Tang <geliangtang@163.com> Signed-off-by: Yan, Zheng <zyan@redhat.com>
2015-10-22Move locks API users to locks_lock_inode_wait()Benjamin Coddington
Instead of having users check for FL_POSIX or FL_FLOCK to call the correct locks API function, use the check within locks_lock_inode_wait(). This allows for some later cleanup. Signed-off-by: Benjamin Coddington <bcodding@redhat.com> Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
2015-09-11Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client Pull Ceph update from Sage Weil: "There are a few fixes for snapshot behavior with CephFS and support for the new keepalive protocol from Zheng, a libceph fix that affects both RBD and CephFS, a few bug fixes and cleanups for RBD from Ilya, and several small fixes and cleanups from Jianpeng and others" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client: ceph: improve readahead for file holes ceph: get inode size for each append write libceph: check data_len in ->alloc_msg() libceph: use keepalive2 to verify the mon session is alive rbd: plug rbd_dev->header.object_prefix memory leak rbd: fix double free on rbd_dev->header_name libceph: set 'exists' flag for newly up osd ceph: cleanup use of ceph_msg_get ceph: no need to get parent inode in ceph_open ceph: remove the useless judgement ceph: remove redundant test of head->safe and silence static analysis warnings ceph: fix queuing inode to mdsdir's snaprealm libceph: rename con_work() to ceph_con_workfn() libceph: Avoid holding the zero page on ceph_msgr_slab_init errors libceph: remove the unused macro AES_KEY_SIZE ceph: invalidate dirty pages after forced umount ceph: EIO all operations after forced umount
2015-09-10mm: mark most vm_operations_struct constKirill A. Shutemov
With two exceptions (drm/qxl and drm/radeon) all vm_operations_struct structs should be constant. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Reviewed-by: Oleg Nesterov <oleg@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Minchan Kim <minchan@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-09ceph: improve readahead for file holesYan, Zheng
When readahead encounters file holes, osd reply returns error -ENOENT, finish_read() skips adding pages to the the page cache. So readahead does not work for file holes. The fix is adding zero pages to the page cache when -ENOENT is returned. Signed-off-by: Yan, Zheng <zyan@redhat.com>
2015-09-09ceph: get inode size for each append writeYan, Zheng
Signed-off-by: Yan, Zheng <zyan@redhat.com>
2015-09-08ceph: cleanup use of ceph_msg_getJianpeng Ma
Signed-off-by: Jianpeng Ma <jianpeng.ma@intel.com> Signed-off-by: Yan, Zheng <zyan@redhat.com>
2015-09-08ceph: no need to get parent inode in ceph_openJianpeng Ma
parent inode is needed in creating new inode case. For ceph_open, the target inode already exists. Signed-off-by: Jianpeng Ma <jianpeng.ma@intel.com> Signed-off-by: Yan, Zheng <zyan@redhat.com>
2015-09-08ceph: remove the useless judgementJianpeng Ma
err != 0 is already handled. So skip this. Signed-off-by: Jianpeng Ma <jianpeng.ma@intel.com> Signed-off-by: Yan, Zheng <zyan@redhat.com>
2015-09-08ceph: remove redundant test of head->safe and silence static analysis warningsBrad Hubbard
Signed-off-by: Brad Hubbard <bhubbard@redhat.com> Signed-off-by: Yan, Zheng <zyan@redhat.com>
2015-09-08ceph: fix queuing inode to mdsdir's snaprealmYan, Zheng
During MDS failovers, MClientSnap message may cause kclient to move some inodes from root directory's snaprealm to mdsdir's snaprealm and queue snapshots for these inodes. For a FS has never created any snapshot, both root directory's snaprealm and mdsdir's snaprealm share the same snapshot contexts (both are ceph_empty_snapc). This confuses ceph_put_wrbuffer_cap_refs(), make it unable to distinguish snapshot buffers from head buffers. The fix is do not use ceph_empty_snapc as snaprealm's cached context. Signed-off-by: Yan, Zheng <zyan@redhat.com>
2015-09-08ceph: invalidate dirty pages after forced umountYan, Zheng
After forced umount, ceph_writepages_start() skips flushing dirty pages. To make sure inode's reference count get dropped to zero, we need to invalidate dirty pages. Signed-off-by: Yan, Zheng <zyan@redhat.com>
2015-09-08ceph: EIO all operations after forced umountYan, Zheng
This patch makes try_get_cap_refs() and __do_request() check if the file system was forced umount, and return -EIO if it was. This patch also adds a helper function to drops dirty caps and wakes up blocking operation. Signed-off-by: Yan, Zheng <zyan@redhat.com>
2015-09-04fs: create and use seq_show_option for escapingKees Cook
Many file systems that implement the show_options hook fail to correctly escape their output which could lead to unescaped characters (e.g. new lines) leaking into /proc/mounts and /proc/[pid]/mountinfo files. This could lead to confusion, spoofed entries (resulting in things like systemd issuing false d-bus "mount" notifications), and who knows what else. This looks like it would only be the root user stepping on themselves, but it's possible weird things could happen in containers or in other situations with delegated mount privileges. Here's an example using overlay with setuid fusermount trusting the contents of /proc/mounts (via the /etc/mtab symlink). Imagine the use of "sudo" is something more sneaky: $ BASE="ovl" $ MNT="$BASE/mnt" $ LOW="$BASE/lower" $ UP="$BASE/upper" $ WORK="$BASE/work/ 0 0 none /proc fuse.pwn user_id=1000" $ mkdir -p "$LOW" "$UP" "$WORK" $ sudo mount -t overlay -o "lowerdir=$LOW,upperdir=$UP,workdir=$WORK" none /mnt $ cat /proc/mounts none /root/ovl/mnt overlay rw,relatime,lowerdir=ovl/lower,upperdir=ovl/upper,workdir=ovl/work/ 0 0 none /proc fuse.pwn user_id=1000 0 0 $ fusermount -u /proc $ cat /proc/mounts cat: /proc/mounts: No such file or directory This fixes the problem by adding new seq_show_option and seq_show_option_n helpers, and updating the vulnerable show_option handlers to use them as needed. Some, like SELinux, need to be open coded due to unusual existing escape mechanisms. [akpm@linux-foundation.org: add lost chunk, per Kees] [keescook@chromium.org: seq_show_option should be using const parameters] Signed-off-by: Kees Cook <keescook@chromium.org> Acked-by: Serge Hallyn <serge.hallyn@canonical.com> Acked-by: Jan Kara <jack@suse.com> Acked-by: Paul Moore <paul@paul-moore.com> Cc: J. R. Okajima <hooanon05g@gmail.com> Signed-off-by: Kees Cook <keescook@chromium.org> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-07-31ceph: always re-send cap flushes when MDS recoversYan, Zheng
commit e548e9b93d3e565e42b938a99804114565be1f81 makes the kclient only re-send cap flush once during MDS failover. If the kclient sends a cap flush after MDS enters reconnect stage but before MDS recovers. The kclient will skip re-sending the same cap flush when MDS recovers. This causes problem for newly created inode. The MDS handles cap flushes before replaying unsafe requests, so it's possible that MDS find corresponding inode is missing when handling cap flush. The fix is reverting to old behaviour: always re-send when MDS recovers Signed-off-by: Yan, Zheng <zyan@redhat.com> Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2015-07-31ceph: fix ceph_encode_locks_to_buffer()Yan, Zheng
posix locks should be in ctx->flc_posix list Signed-off-by: Yan, Zheng <zyan@redhat.com> Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2015-07-04Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull more vfs updates from Al Viro: "Assorted VFS fixes and related cleanups (IMO the most interesting in that part are f_path-related things and Eric's descriptor-related stuff). UFS regression fixes (it got broken last cycle). 9P fixes. fs-cache series, DAX patches, Jan's file_remove_suid() work" [ I'd say this is much more than "fixes and related cleanups". The file_table locking rule change by Eric Dumazet is a rather big and fundamental update even if the patch isn't huge. - Linus ] * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (49 commits) 9p: cope with bogus responses from server in p9_client_{read,write} p9_client_write(): avoid double p9_free_req() 9p: forgetting to cancel request on interrupted zero-copy RPC dax: bdev_direct_access() may sleep block: Add support for DAX reads/writes to block devices dax: Use copy_from_iter_nocache dax: Add block size note to documentation fs/file.c: __fget() and dup2() atomicity rules fs/file.c: don't acquire files->file_lock in fd_install() fs:super:get_anon_bdev: fix race condition could cause dev exceed its upper limitation vfs: avoid creation of inode number 0 in get_next_ino namei: make set_root_rcu() return void make simple_positive() public ufs: use dir_pages instead of ufs_dir_pages() pagemap.h: move dir_pages() over there remove the pointless include of lglock.h fs: cleanup slight list_entry abuse xfs: Correctly lock inode when removing suid and file capabilities fs: Call security_ops->inode_killpriv on truncate fs: Provide function telling whether file_remove_privs() will do anything ...
2015-07-02Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client Pull Ceph updates from Sage Weil: "We have a pile of bug fixes from Ilya, including a few patches that sync up the CRUSH code with the latest from userspace. There is also a long series from Zheng that fixes various issues with snapshots, inline data, and directory fsync, some simplification and improvement in the cap release code, and a rework of the caching of directory contents. To top it off there are a few small fixes and cleanups from Benoit and Hong" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client: (40 commits) rbd: use GFP_NOIO in rbd_obj_request_create() crush: fix a bug in tree bucket decode libceph: Fix ceph_tcp_sendpage()'s more boolean usage libceph: Remove spurious kunmap() of the zero page rbd: queue_depth map option rbd: store rbd_options in rbd_device rbd: terminate rbd_opts_tokens with Opt_err ceph: fix ceph_writepages_start() rbd: bump queue_max_segments ceph: rework dcache readdir crush: sync up with userspace crush: fix crash from invalid 'take' argument ceph: switch some GFP_NOFS memory allocation to GFP_KERNEL ceph: pre-allocate data structure that tracks caps flushing ceph: re-send flushing caps (which are revoked) in reconnect stage ceph: send TID of the oldest pending caps flush to MDS ceph: track pending caps flushing globally ceph: track pending caps flushing accurately libceph: fix wrong name "Ceph filesystem for Linux" ceph: fix directory fsync ...
2015-06-25ceph: fix ceph_writepages_start()Yan, Zheng
Before a page get locked, someone else can write data to the page and increase the i_size. So we should re-check the i_size after pages are locked. Signed-off-by: Yan, Zheng <zyan@redhat.com>
2015-06-25ceph: rework dcache readdirYan, Zheng
Previously our dcache readdir code relies on that child dentries in directory dentry's d_subdir list are sorted by dentry's offset in descending order. When adding dentries to the dcache, if a dentry already exists, our readdir code moves it to head of directory dentry's d_subdir list. This design relies on dcache internals. Al Viro suggests using ncpfs's approach: keeping array of pointers to dentries in page cache of directory inode. the validity of those pointers are presented by directory inode's complete and ordered flags. When a dentry gets pruned, we clear directory inode's complete flag in the d_prune() callback. Before moving a dentry to other directory, we clear the ordered flag for both old and new directory. Signed-off-by: Yan, Zheng <zyan@redhat.com>
2015-06-25ceph: switch some GFP_NOFS memory allocation to GFP_KERNELYan, Zheng
GFP_NOFS memory allocation is required for page writeback path. But there is no need to use GFP_NOFS in syscall path and readpage path Signed-off-by: Yan, Zheng <zyan@redhat.com>
2015-06-25ceph: pre-allocate data structure that tracks caps flushingYan, Zheng
Signed-off-by: Yan, Zheng <zyan@redhat.com>
2015-06-25ceph: re-send flushing caps (which are revoked) in reconnect stageYan, Zheng
if flushing caps were revoked, we should re-send the cap flush in client reconnect stage. This guarantees that MDS processes the cap flush message before issuing the flushing caps to other client. Signed-off-by: Yan, Zheng <zyan@redhat.com>
2015-06-25ceph: send TID of the oldest pending caps flush to MDSYan, Zheng
According to this information, MDS can trim its completed caps flush list (which is used to detect duplicated cap flush). Signed-off-by: Yan, Zheng <zyan@redhat.com>
2015-06-25ceph: track pending caps flushing globallyYan, Zheng
So we know TID of the oldest pending caps flushing. Later patch will send this information to MDS, so that MDS can trim its completed caps flush list. Tracking pending caps flushing globally also simplifies syncfs code. Signed-off-by: Yan, Zheng <zyan@redhat.com>
2015-06-25ceph: track pending caps flushing accuratelyYan, Zheng
Previously we do not trace accurate TID for flushing caps. when MDS failovers, we have no choice but to re-send all flushing caps with a new TID. This can cause problem because MDS can has already flushed some caps and has issued the same caps to other client. The re-sent cap flush has a new TID, which makes MDS unable to detect if it has already processed the cap flush. This patch adds code to track pending caps flushing accurately. When re-sending cap flush is needed, we use its original flush TID. Signed-off-by: Yan, Zheng <zyan@redhat.com>
2015-06-25ceph: fix directory fsyncYan, Zheng
fsync() on directory should flush dirty caps and wait for any uncommitted directory opertions to commit. But ceph_dir_fsync() only waits for uncommitted directory opertions. Signed-off-by: Yan, Zheng <zyan@redhat.com>
2015-06-25ceph: fix flushing capsYan, Zheng
Current ceph_fsync() only flushes dirty caps and wait for them to be flushed. It doesn't wait for caps that has already been flushing. This patch makes ceph_fsync() wait for pending flushing caps too. Besides, this patch also makes caps_are_flushed() peroperly handle tid wrapping. Signed-off-by: Yan, Zheng <zyan@redhat.com>
2015-06-25ceph: don't include used caps in cap_wantedYan, Zheng
when copying files to cephfs, file data may stay in page cache after corresponding file is closed. Cached data use Fc capability. If we include Fc capability in cap_wanted, MDS will treat files with cached data as open files, and journal them in an EOpen event when trimming log segment. Signed-off-by: Yan, Zheng <zyan@redhat.com>
2015-06-25ceph: ratelimit warn messages for MDS closes sessionYan, Zheng
Signed-off-by: Yan, Zheng <zyan@redhat.com>
2015-06-25ceph: simplify two mount_timeout sitesIlya Dryomov
No need to bifurcate wait now that we've got ceph_timeout_jiffies(). Signed-off-by: Ilya Dryomov <idryomov@gmail.com> Reviewed-by: Alex Elder <elder@linaro.org> Reviewed-by: Yan, Zheng <zyan@redhat.com>
2015-06-25libceph: store timeouts in jiffies, verify user inputIlya Dryomov
There are currently three libceph-level timeouts that the user can specify on mount: mount_timeout, osd_idle_ttl and osdkeepalive. All of these are in seconds and no checking is done on user input: negative values are accepted, we multiply them all by HZ which may or may not overflow, arbitrarily large jiffies then get added together, etc. There is also a bug in the way mount_timeout=0 is handled. It's supposed to mean "infinite timeout", but that's not how wait.h APIs treat it and so __ceph_open_session() for example will busy loop without much chance of being interrupted if none of ceph-mons are there. Fix all this by verifying user input, storing timeouts capped by msecs_to_jiffies() in jiffies and using the new ceph_timeout_jiffies() helper for all user-specified waits to handle infinite timeouts correctly. Signed-off-by: Ilya Dryomov <idryomov@gmail.com> Reviewed-by: Alex Elder <elder@linaro.org>
2015-06-25ceph: exclude setfilelock requests when calculating oldest tidYan, Zheng
setfilelock requests can block for a long time, which can prevent client from advancing its oldest tid. Signed-off-by: Yan, Zheng <zyan@redhat.com>
2015-06-25ceph: don't pre-allocate space for cap release messagesYan, Zheng
Previously we pre-allocate cap release messages for each caps. This wastes lots of memory when there are large amount of caps. This patch make the code not pre-allocate the cap release messages. Instead, we add the corresponding ceph_cap struct to a list when releasing a cap. Later when flush cap releases is needed, we allocate the cap release messages dynamically. Signed-off-by: Yan, Zheng <zyan@redhat.com>
2015-06-25ceph: make sure syncfs flushes all cap snapsYan, Zheng
Signed-off-by: Yan, Zheng <zyan@redhat.com>
2015-06-25ceph: don't trim auth cap when there are cap snapsYan, Zheng
Signed-off-by: Yan, Zheng <zyan@redhat.com>
2015-06-25ceph: take snap_rwsem when accessing snap realm's cached_contextYan, Zheng
When ceph inode's i_head_snapc is NULL, __ceph_mark_dirty_caps() accesses snap realm's cached_context. So we need take read lock of snap_rwsem. Signed-off-by: Yan, Zheng <zyan@redhat.com>
2015-06-25ceph: avoid sending unnessesary FLUSHSNAP messageYan, Zheng
when a snap notification contains no new snapshot, we can avoid sending FLUSHSNAP message to MDS. But we still need to create cap_snap in some case because it's required by write path and page writeback path Signed-off-by: Yan, Zheng <zyan@redhat.com>
2015-06-25ceph: set i_head_snapc when getting CEPH_CAP_FILE_WR referenceYan, Zheng
In most cases that snap context is needed, we are holding reference of CEPH_CAP_FILE_WR. So we can set ceph inode's i_head_snapc when getting the CEPH_CAP_FILE_WR reference, and make codes get snap context from i_head_snapc. This makes the code simpler. Another benefit of this change is that we can handle snap notification more elegantly. Especially when snap context is updated while someone else is doing write. The old queue cap_snap code may set cap_snap's context to ether the old context or the new snap context, depending on if i_head_snapc is set. The new queue capp_snap code always set cap_snap's context to the old snap context. Signed-off-by: Yan, Zheng <zyan@redhat.com>