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author | Yan, Zheng <zyan@redhat.com> | 2015-05-01 17:49:16 +0800 |
---|---|---|
committer | Ilya Dryomov <idryomov@gmail.com> | 2015-06-25 11:49:28 +0300 |
commit | 604d1b0245b97738cde4341944ad93edff4b2827 (patch) | |
tree | 05a75dfc1ddf4729405f9cb6ce2f405b8e47791e /fs/ceph/xattr.c | |
parent | 860560904962d08fd38666207c910065fe53e074 (diff) | |
download | linux-stable-604d1b0245b97738cde4341944ad93edff4b2827.tar.gz linux-stable-604d1b0245b97738cde4341944ad93edff4b2827.tar.bz2 linux-stable-604d1b0245b97738cde4341944ad93edff4b2827.zip |
ceph: take snap_rwsem when accessing snap realm's cached_context
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>
Diffstat (limited to 'fs/ceph/xattr.c')
-rw-r--r-- | fs/ceph/xattr.c | 45 |
1 files changed, 39 insertions, 6 deletions
diff --git a/fs/ceph/xattr.c b/fs/ceph/xattr.c index cd7ffad4041d..c6f7d9b82085 100644 --- a/fs/ceph/xattr.c +++ b/fs/ceph/xattr.c @@ -911,6 +911,7 @@ int __ceph_setxattr(struct dentry *dentry, const char *name, struct inode *inode = d_inode(dentry); struct ceph_vxattr *vxattr; struct ceph_inode_info *ci = ceph_inode(inode); + struct ceph_mds_client *mdsc = ceph_sb_to_client(dentry->d_sb)->mdsc; int issued; int err; int dirty = 0; @@ -920,6 +921,7 @@ int __ceph_setxattr(struct dentry *dentry, const char *name, char *newval = NULL; struct ceph_inode_xattr *xattr = NULL; int required_blob_size; + bool lock_snap_rwsem = false; if (!ceph_is_valid_xattr(name)) return -EOPNOTSUPP; @@ -951,9 +953,20 @@ int __ceph_setxattr(struct dentry *dentry, const char *name, spin_lock(&ci->i_ceph_lock); retry: issued = __ceph_caps_issued(ci, NULL); - dout("setxattr %p issued %s\n", inode, ceph_cap_string(issued)); if (ci->i_xattrs.version == 0 || !(issued & CEPH_CAP_XATTR_EXCL)) goto do_sync; + + if (!lock_snap_rwsem && !ci->i_head_snapc) { + lock_snap_rwsem = true; + if (!down_read_trylock(&mdsc->snap_rwsem)) { + spin_unlock(&ci->i_ceph_lock); + down_read(&mdsc->snap_rwsem); + spin_lock(&ci->i_ceph_lock); + goto retry; + } + } + + dout("setxattr %p issued %s\n", inode, ceph_cap_string(issued)); __build_xattrs(inode); required_blob_size = __get_required_blob_size(ci, name_len, val_len); @@ -966,7 +979,7 @@ retry: dout(" preaallocating new blob size=%d\n", required_blob_size); blob = ceph_buffer_new(required_blob_size, GFP_NOFS); if (!blob) - goto out; + goto do_sync_unlocked; spin_lock(&ci->i_ceph_lock); if (ci->i_xattrs.prealloc_blob) ceph_buffer_put(ci->i_xattrs.prealloc_blob); @@ -984,6 +997,8 @@ retry: } spin_unlock(&ci->i_ceph_lock); + if (lock_snap_rwsem) + up_read(&mdsc->snap_rwsem); if (dirty) __mark_inode_dirty(inode, dirty); return err; @@ -991,6 +1006,8 @@ retry: do_sync: spin_unlock(&ci->i_ceph_lock); do_sync_unlocked: + if (lock_snap_rwsem) + up_read(&mdsc->snap_rwsem); err = ceph_sync_setxattr(dentry, name, value, size, flags); out: kfree(newname); @@ -1044,10 +1061,12 @@ int __ceph_removexattr(struct dentry *dentry, const char *name) struct inode *inode = d_inode(dentry); struct ceph_vxattr *vxattr; struct ceph_inode_info *ci = ceph_inode(inode); + struct ceph_mds_client *mdsc = ceph_sb_to_client(dentry->d_sb)->mdsc; int issued; int err; int required_blob_size; int dirty; + bool lock_snap_rwsem = false; if (!ceph_is_valid_xattr(name)) return -EOPNOTSUPP; @@ -1064,10 +1083,21 @@ int __ceph_removexattr(struct dentry *dentry, const char *name) spin_lock(&ci->i_ceph_lock); retry: issued = __ceph_caps_issued(ci, NULL); - dout("removexattr %p issued %s\n", inode, ceph_cap_string(issued)); - if (ci->i_xattrs.version == 0 || !(issued & CEPH_CAP_XATTR_EXCL)) goto do_sync; + + if (!lock_snap_rwsem && !ci->i_head_snapc) { + lock_snap_rwsem = true; + if (!down_read_trylock(&mdsc->snap_rwsem)) { + spin_unlock(&ci->i_ceph_lock); + down_read(&mdsc->snap_rwsem); + spin_lock(&ci->i_ceph_lock); + goto retry; + } + } + + dout("removexattr %p issued %s\n", inode, ceph_cap_string(issued)); + __build_xattrs(inode); required_blob_size = __get_required_blob_size(ci, 0, 0); @@ -1080,7 +1110,7 @@ retry: dout(" preaallocating new blob size=%d\n", required_blob_size); blob = ceph_buffer_new(required_blob_size, GFP_NOFS); if (!blob) - goto out; + goto do_sync_unlocked; spin_lock(&ci->i_ceph_lock); if (ci->i_xattrs.prealloc_blob) ceph_buffer_put(ci->i_xattrs.prealloc_blob); @@ -1094,14 +1124,17 @@ retry: ci->i_xattrs.dirty = true; inode->i_ctime = CURRENT_TIME; spin_unlock(&ci->i_ceph_lock); + if (lock_snap_rwsem) + up_read(&mdsc->snap_rwsem); if (dirty) __mark_inode_dirty(inode, dirty); return err; do_sync: spin_unlock(&ci->i_ceph_lock); do_sync_unlocked: + if (lock_snap_rwsem) + up_read(&mdsc->snap_rwsem); err = ceph_send_removexattr(dentry, name); -out: return err; } |