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ceph: use i_release_count to indicate dir's completeness
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Current ceph code tracks directory's completeness in two places.
ceph_readdir() checks i_release_count to decide if it can set the
I_COMPLETE flag in i_ceph_flags. All other places check the I_COMPLETE
flag. This indirection introduces locking complexity.

This patch adds a new variable i_complete_count to ceph_inode_info.
Set i_release_count's value to it when marking a directory complete.
By comparing the two variables, we know if a directory is complete

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
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Yan, Zheng authored and Sage Weil committed May 2, 2013
1 parent 8a166d0 commit 2f276c5
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Showing 5 changed files with 45 additions and 49 deletions.
4 changes: 2 additions & 2 deletions fs/ceph/caps.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -490,7 +490,7 @@ static void __check_cap_issue(struct ceph_inode_info *ci, struct ceph_cap *cap,
ci->i_rdcache_gen++;

/*
* if we are newly issued FILE_SHARED, clear I_COMPLETE; we
* if we are newly issued FILE_SHARED, mark dir not complete; we
* don't know what happened to this directory while we didn't
* have the cap.
*/
Expand All @@ -499,7 +499,7 @@ static void __check_cap_issue(struct ceph_inode_info *ci, struct ceph_cap *cap,
ci->i_shared_gen++;
if (S_ISDIR(ci->vfs_inode.i_mode)) {
dout(" marking %p NOT complete\n", &ci->vfs_inode);
ci->i_ceph_flags &= ~CEPH_I_COMPLETE;
__ceph_dir_clear_complete(ci);
}
}
}
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25 changes: 13 additions & 12 deletions fs/ceph/dir.c
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Original file line number Diff line number Diff line change
Expand Up @@ -107,7 +107,7 @@ static unsigned fpos_off(loff_t p)
* falling back to a "normal" sync readdir if any dentries in the dir
* are dropped.
*
* I_COMPLETE tells indicates we have all dentries in the dir. It is
* Complete dir indicates that we have all dentries in the dir. It is
* defined IFF we hold CEPH_CAP_FILE_SHARED (which will be revoked by
* the MDS if/when the directory is modified).
*/
Expand Down Expand Up @@ -198,8 +198,8 @@ static int __dcache_readdir(struct file *filp,
filp->f_pos++;

/* make sure a dentry wasn't dropped while we didn't have parent lock */
if (!ceph_i_test(dir, CEPH_I_COMPLETE)) {
dout(" lost I_COMPLETE on %p; falling back to mds\n", dir);
if (!ceph_dir_is_complete(dir)) {
dout(" lost dir complete on %p; falling back to mds\n", dir);
err = -EAGAIN;
goto out;
}
Expand Down Expand Up @@ -258,7 +258,7 @@ static int ceph_readdir(struct file *filp, void *dirent, filldir_t filldir)
if (filp->f_pos == 0) {
/* note dir version at start of readdir so we can tell
* if any dentries get dropped */
fi->dir_release_count = ci->i_release_count;
fi->dir_release_count = atomic_read(&ci->i_release_count);

dout("readdir off 0 -> '.'\n");
if (filldir(dirent, ".", 1, ceph_make_fpos(0, 0),
Expand All @@ -284,7 +284,7 @@ static int ceph_readdir(struct file *filp, void *dirent, filldir_t filldir)
if ((filp->f_pos == 2 || fi->dentry) &&
!ceph_test_mount_opt(fsc, NOASYNCREADDIR) &&
ceph_snap(inode) != CEPH_SNAPDIR &&
(ci->i_ceph_flags & CEPH_I_COMPLETE) &&
__ceph_dir_is_complete(ci) &&
__ceph_caps_issued_mask(ci, CEPH_CAP_FILE_SHARED, 1)) {
spin_unlock(&ci->i_ceph_lock);
err = __dcache_readdir(filp, dirent, filldir);
Expand Down Expand Up @@ -350,7 +350,8 @@ static int ceph_readdir(struct file *filp, void *dirent, filldir_t filldir)

if (!req->r_did_prepopulate) {
dout("readdir !did_prepopulate");
fi->dir_release_count--; /* preclude I_COMPLETE */
/* preclude from marking dir complete */
fi->dir_release_count--;
}

/* note next offset and last dentry name */
Expand Down Expand Up @@ -428,9 +429,9 @@ static int ceph_readdir(struct file *filp, void *dirent, filldir_t filldir)
* the complete dir contents in our cache.
*/
spin_lock(&ci->i_ceph_lock);
if (ci->i_release_count == fi->dir_release_count) {
if (atomic_read(&ci->i_release_count) == fi->dir_release_count) {
dout(" marking %p complete\n", inode);
ci->i_ceph_flags |= CEPH_I_COMPLETE;
__ceph_dir_set_complete(ci, fi->dir_release_count);
ci->i_max_offset = filp->f_pos;
}
spin_unlock(&ci->i_ceph_lock);
Expand Down Expand Up @@ -605,7 +606,7 @@ static struct dentry *ceph_lookup(struct inode *dir, struct dentry *dentry,
fsc->mount_options->snapdir_name,
dentry->d_name.len) &&
!is_root_ceph_dentry(dir, dentry) &&
(ci->i_ceph_flags & CEPH_I_COMPLETE) &&
__ceph_dir_is_complete(ci) &&
(__ceph_caps_issued_mask(ci, CEPH_CAP_FILE_SHARED, 1))) {
spin_unlock(&ci->i_ceph_lock);
dout(" dir %p complete, -ENOENT\n", dir);
Expand Down Expand Up @@ -909,7 +910,7 @@ static int ceph_rename(struct inode *old_dir, struct dentry *old_dentry,
*/

/* d_move screws up d_subdirs order */
ceph_i_clear(new_dir, CEPH_I_COMPLETE);
ceph_dir_clear_complete(new_dir);

d_move(old_dentry, new_dentry);

Expand Down Expand Up @@ -1079,15 +1080,15 @@ static void ceph_d_prune(struct dentry *dentry)
if (IS_ROOT(dentry))
return;

/* if we are not hashed, we don't affect I_COMPLETE */
/* if we are not hashed, we don't affect dir's completeness */
if (d_unhashed(dentry))
return;

/*
* we hold d_lock, so d_parent is stable, and d_fsdata is never
* cleared until d_release
*/
ceph_i_clear(dentry->d_parent->d_inode, CEPH_I_COMPLETE);
ceph_dir_clear_complete(dentry->d_parent->d_inode);
}

/*
Expand Down
13 changes: 7 additions & 6 deletions fs/ceph/inode.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -302,7 +302,8 @@ struct inode *ceph_alloc_inode(struct super_block *sb)
ci->i_version = 0;
ci->i_time_warp_seq = 0;
ci->i_ceph_flags = 0;
ci->i_release_count = 0;
atomic_set(&ci->i_release_count, 1);
atomic_set(&ci->i_complete_count, 0);
ci->i_symlink = NULL;

memset(&ci->i_dir_layout, 0, sizeof(ci->i_dir_layout));
Expand Down Expand Up @@ -721,9 +722,9 @@ static int fill_inode(struct inode *inode,
ceph_snap(inode) == CEPH_NOSNAP &&
(le32_to_cpu(info->cap.caps) & CEPH_CAP_FILE_SHARED) &&
(issued & CEPH_CAP_FILE_EXCL) == 0 &&
(ci->i_ceph_flags & CEPH_I_COMPLETE) == 0) {
!__ceph_dir_is_complete(ci)) {
dout(" marking %p complete (empty)\n", inode);
ci->i_ceph_flags |= CEPH_I_COMPLETE;
__ceph_dir_set_complete(ci, atomic_read(&ci->i_release_count));
ci->i_max_offset = 2;
}
no_change:
Expand Down Expand Up @@ -857,7 +858,7 @@ static void ceph_set_dentry_offset(struct dentry *dn)
di = ceph_dentry(dn);

spin_lock(&ci->i_ceph_lock);
if ((ceph_inode(inode)->i_ceph_flags & CEPH_I_COMPLETE) == 0) {
if (!__ceph_dir_is_complete(ci)) {
spin_unlock(&ci->i_ceph_lock);
return;
}
Expand Down Expand Up @@ -1061,8 +1062,8 @@ int ceph_fill_trace(struct super_block *sb, struct ceph_mds_request *req,
/*
* d_move() puts the renamed dentry at the end of
* d_subdirs. We need to assign it an appropriate
* directory offset so we can behave when holding
* I_COMPLETE.
* directory offset so we can behave when dir is
* complete.
*/
ceph_set_dentry_offset(req->r_old_dentry);
dout("dn %p gets new offset %lld\n", req->r_old_dentry,
Expand Down
10 changes: 3 additions & 7 deletions fs/ceph/mds_client.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -2034,20 +2034,16 @@ int ceph_mdsc_do_request(struct ceph_mds_client *mdsc,
}

/*
* Invalidate dir I_COMPLETE, dentry lease state on an aborted MDS
* Invalidate dir's completeness, dentry lease state on an aborted MDS
* namespace request.
*/
void ceph_invalidate_dir_request(struct ceph_mds_request *req)
{
struct inode *inode = req->r_locked_dir;
struct ceph_inode_info *ci = ceph_inode(inode);

dout("invalidate_dir_request %p (I_COMPLETE, lease(s))\n", inode);
spin_lock(&ci->i_ceph_lock);
ci->i_ceph_flags &= ~CEPH_I_COMPLETE;
ci->i_release_count++;
spin_unlock(&ci->i_ceph_lock);
dout("invalidate_dir_request %p (complete, lease(s))\n", inode);

ceph_dir_clear_complete(inode);
if (req->r_dentry)
ceph_invalidate_dentry_lease(req->r_dentry);
if (req->r_old_dentry)
Expand Down
42 changes: 20 additions & 22 deletions fs/ceph/super.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -244,7 +244,8 @@ struct ceph_inode_info {
u32 i_time_warp_seq;

unsigned i_ceph_flags;
unsigned long i_release_count;
atomic_t i_release_count;
atomic_t i_complete_count;

struct ceph_dir_layout i_dir_layout;
struct ceph_file_layout i_layout;
Expand All @@ -254,7 +255,7 @@ struct ceph_inode_info {
struct timespec i_rctime;
u64 i_rbytes, i_rfiles, i_rsubdirs;
u64 i_files, i_subdirs;
u64 i_max_offset; /* largest readdir offset, set with I_COMPLETE */
u64 i_max_offset; /* largest readdir offset, set with complete dir */

struct rb_root i_fragtree;
struct mutex i_fragtree_mutex;
Expand Down Expand Up @@ -419,38 +420,35 @@ static inline struct inode *ceph_find_inode(struct super_block *sb,
/*
* Ceph inode.
*/
#define CEPH_I_COMPLETE 1 /* we have complete directory cached */
#define CEPH_I_NODELAY 4 /* do not delay cap release */
#define CEPH_I_FLUSH 8 /* do not delay flush of dirty metadata */
#define CEPH_I_NOFLUSH 16 /* do not flush dirty caps */

static inline void ceph_i_clear(struct inode *inode, unsigned mask)
static inline void __ceph_dir_set_complete(struct ceph_inode_info *ci,
int release_count)
{
struct ceph_inode_info *ci = ceph_inode(inode);

spin_lock(&ci->i_ceph_lock);
ci->i_ceph_flags &= ~mask;
spin_unlock(&ci->i_ceph_lock);
atomic_set(&ci->i_complete_count, release_count);
}

static inline void ceph_i_set(struct inode *inode, unsigned mask)
static inline void __ceph_dir_clear_complete(struct ceph_inode_info *ci)
{
struct ceph_inode_info *ci = ceph_inode(inode);
atomic_inc(&ci->i_release_count);
}

spin_lock(&ci->i_ceph_lock);
ci->i_ceph_flags |= mask;
spin_unlock(&ci->i_ceph_lock);
static inline bool __ceph_dir_is_complete(struct ceph_inode_info *ci)
{
return atomic_read(&ci->i_complete_count) ==
atomic_read(&ci->i_release_count);
}

static inline bool ceph_i_test(struct inode *inode, unsigned mask)
static inline void ceph_dir_clear_complete(struct inode *inode)
{
struct ceph_inode_info *ci = ceph_inode(inode);
bool r;
__ceph_dir_clear_complete(ceph_inode(inode));
}

spin_lock(&ci->i_ceph_lock);
r = (ci->i_ceph_flags & mask) == mask;
spin_unlock(&ci->i_ceph_lock);
return r;
static inline bool ceph_dir_is_complete(struct inode *inode)
{
return __ceph_dir_is_complete(ceph_inode(inode));
}


Expand Down Expand Up @@ -565,7 +563,7 @@ struct ceph_file_info {
u64 next_offset; /* offset of next chunk (last_name's + 1) */
char *last_name; /* last entry in previous chunk */
struct dentry *dentry; /* next dentry (for dcache readdir) */
unsigned long dir_release_count;
int dir_release_count;

/* used for -o dirstat read() on directory thing */
char *dir_info;
Expand Down

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