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ceph: fix freeing inode vs removing session caps race

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remove_session_caps() uses iterate_session_caps() to remove caps,
but iterate_session_caps() skips inodes that are being deleted.
So session->s_nr_caps can be non-zero after iterate_session_caps()
return.

We can fix the issue by waiting until deletions are complete.
__wait_on_freeing_inode() is designed for the job, but it is not
exported, so we use lookup inode function to access it.

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
This commit is contained in:
Yan, Zheng 2013-07-24 12:22:11 +08:00 committed by Sage Weil
parent 4d1829a59d
commit 6f60f88947
3 changed files with 41 additions and 0 deletions
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8
fs/ceph/inode.c
View File

@ -61,6 +61,14 @@ struct inode *ceph_get_inode(struct super_block *sb, struct ceph_vino vino)
return inode;
}
struct inode *ceph_lookup_inode(struct super_block *sb, struct ceph_vino vino)
{
struct inode *inode;
ino_t t = ceph_vino_to_ino(vino);
inode = ilookup5_nowait(sb, t, ceph_ino_compare, &vino);
return inode;
}
/*
* get/constuct snapdir inode for a given directory
*/

31
fs/ceph/mds_client.c
View File

@ -1031,6 +1031,37 @@ static void remove_session_caps(struct ceph_mds_session *session)
{
dout("remove_session_caps on %p\n", session);
iterate_session_caps(session, remove_session_caps_cb, NULL);
spin_lock(&session->s_cap_lock);
if (session->s_nr_caps > 0) {
struct super_block *sb = session->s_mdsc->fsc->sb;
struct inode *inode;
struct ceph_cap *cap, *prev = NULL;
struct ceph_vino vino;
/*
* iterate_session_caps() skips inodes that are being
* deleted, we need to wait until deletions are complete.
* __wait_on_freeing_inode() is designed for the job,
* but it is not exported, so use lookup inode function
* to access it.
*/
while (!list_empty(&session->s_caps)) {
cap = list_entry(session->s_caps.next,
struct ceph_cap, session_caps);
if (cap == prev)
break;
prev = cap;
vino = cap->ci->i_vino;
spin_unlock(&session->s_cap_lock);
inode = ceph_lookup_inode(sb, vino);
iput(inode);
spin_lock(&session->s_cap_lock);
}
}
spin_unlock(&session->s_cap_lock);
BUG_ON(session->s_nr_caps > 0);
BUG_ON(!list_empty(&session->s_cap_flushing));
cleanup_cap_releases(session);

2
fs/ceph/super.h
View File

@ -677,6 +677,8 @@ extern void ceph_destroy_inode(struct inode *inode);
extern struct inode *ceph_get_inode(struct super_block *sb,
struct ceph_vino vino);
extern struct inode *ceph_lookup_inode(struct super_block *sb,
struct ceph_vino vino);
extern struct inode *ceph_get_snapdir(struct inode *parent);
extern int ceph_fill_file_size(struct inode *inode, int issued,
u32 truncate_seq, u64 truncate_size, u64 size);