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Commit 70db4f36 authored by Yan, Zheng's avatar Yan, Zheng Committed by Ilya Dryomov
Browse files

ceph: introduce a new inode flag indicating if cached dentries are ordered 



After creating/deleting/renaming file, offsets of sibling dentries may
change. So we can not use cached dentries to satisfy readdir. But we can
still use the cached dentries to conclude -ENOENT for lookup.

This patch introduces a new inode flag indicating if child dentries are
ordered. The flag is set at the same time marking a directory complete.
After creating/deleting/renaming file, we clear the flag on directory
inode. This prevents ceph_readdir() from using cached dentries to satisfy
readdir syscall.

Signed-off-by: default avatarYan, Zheng <zyan@redhat.com>
parent 4965fc38

fs/ceph/dir.c

+15 −8
Original line number Diff line number Diff line
@@ -183,7 +183,7 @@ static int __dcache_readdir(struct file *file, struct dir_context *ctx, 
	spin_unlock(&parent->d_lock);



	/* make sure a dentry wasn't dropped while we didn't have parent lock */

	if (!ceph_dir_is_complete(dir)) {

	if (!ceph_dir_is_complete_ordered(dir)) {

		dout(" lost dir complete on %p; falling back to mds\n", dir);

		dput(dentry);

		err = -EAGAIN;
@@ -261,10 +261,6 @@ static int ceph_readdir(struct file *file, struct dir_context *ctx) 


	/* always start with . and .. */

	if (ctx->pos == 0) {

		/* note dir version at start of readdir so we can tell

		 * if any dentries get dropped */

		fi->dir_release_count = atomic_read(&ci->i_release_count);



		dout("readdir off 0 -> '.'\n");

		if (!dir_emit(ctx, ".", 1, 

			    ceph_translate_ino(inode->i_sb, inode->i_ino),
@@ -289,7 +285,7 @@ static int ceph_readdir(struct file *file, struct dir_context *ctx) 
	if ((ctx->pos == 2 || fi->dentry) &&

	    !ceph_test_mount_opt(fsc, NOASYNCREADDIR) &&

	    ceph_snap(inode) != CEPH_SNAPDIR &&

	    __ceph_dir_is_complete(ci) &&

	    __ceph_dir_is_complete_ordered(ci) &&

	    __ceph_caps_issued_mask(ci, CEPH_CAP_FILE_SHARED, 1)) {

		u32 shared_gen = ci->i_shared_gen;

		spin_unlock(&ci->i_ceph_lock);
@@ -312,6 +308,13 @@ static int ceph_readdir(struct file *file, struct dir_context *ctx) 


	/* proceed with a normal readdir */



	if (ctx->pos == 2) {

		/* note dir version at start of readdir so we can tell

		 * if any dentries get dropped */

		fi->dir_release_count = atomic_read(&ci->i_release_count);

		fi->dir_ordered_count = ci->i_ordered_count;

	}



more:

	/* do we have the correct frag content buffered? */

	if (fi->frag != frag || fi->last_readdir == NULL) {
@@ -446,8 +449,12 @@ static int ceph_readdir(struct file *file, struct dir_context *ctx) 
	 */

	spin_lock(&ci->i_ceph_lock);

	if (atomic_read(&ci->i_release_count) == fi->dir_release_count) {

		if (ci->i_ordered_count == fi->dir_ordered_count)

			dout(" marking %p complete and ordered\n", inode);

		else

			dout(" marking %p complete\n", inode);

		__ceph_dir_set_complete(ci, fi->dir_release_count);

		__ceph_dir_set_complete(ci, fi->dir_release_count,

					fi->dir_ordered_count);

	}

	spin_unlock(&ci->i_ceph_lock);

fs/ceph/inode.c

+8 −5
Original line number Diff line number Diff line
@@ -389,6 +389,7 @@ 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_ordered_count = 0;

	atomic_set(&ci->i_release_count, 1);

	atomic_set(&ci->i_complete_count, 0);

	ci->i_symlink = NULL;
@@ -845,7 +846,8 @@ static int fill_inode(struct inode *inode, 
	    (issued & CEPH_CAP_FILE_EXCL) == 0 &&

	    !__ceph_dir_is_complete(ci)) {

		dout(" marking %p complete (empty)\n", inode);

		__ceph_dir_set_complete(ci, atomic_read(&ci->i_release_count));

		__ceph_dir_set_complete(ci, atomic_read(&ci->i_release_count),

					ci->i_ordered_count);

	}



	/* were we issued a capability? */
@@ -1206,8 +1208,8 @@ int ceph_fill_trace(struct super_block *sb, struct ceph_mds_request *req, 
			ceph_invalidate_dentry_lease(dn);



			/* d_move screws up sibling dentries' offsets */

			ceph_dir_clear_complete(dir);

			ceph_dir_clear_complete(olddir);

			ceph_dir_clear_ordered(dir);

			ceph_dir_clear_ordered(olddir);



			dout("dn %p gets new offset %lld\n", req->r_old_dentry,

			     ceph_dentry(req->r_old_dentry)->offset);
@@ -1219,6 +1221,7 @@ int ceph_fill_trace(struct super_block *sb, struct ceph_mds_request *req, 
		if (!rinfo->head->is_target) {

			dout("fill_trace null dentry\n");

			if (dn->d_inode) {

				ceph_dir_clear_ordered(dir);

				dout("d_delete %p\n", dn);

				d_delete(dn);

			} else {
@@ -1235,7 +1238,7 @@ int ceph_fill_trace(struct super_block *sb, struct ceph_mds_request *req, 


		/* attach proper inode */

		if (!dn->d_inode) {

			ceph_dir_clear_complete(dir);

			ceph_dir_clear_ordered(dir);

			ihold(in);

			dn = splice_dentry(dn, in, &have_lease);

			if (IS_ERR(dn)) {
@@ -1265,7 +1268,7 @@ int ceph_fill_trace(struct super_block *sb, struct ceph_mds_request *req, 
		BUG_ON(!dir);

		BUG_ON(ceph_snap(dir) != CEPH_SNAPDIR);

		dout(" linking snapped dir %p to dn %p\n", in, dn);

		ceph_dir_clear_complete(dir);

		ceph_dir_clear_ordered(dir);

		ihold(in);

		dn = splice_dentry(dn, in, NULL);

		if (IS_ERR(dn)) {

fs/ceph/super.h

+32 −6
Original line number Diff line number Diff line
@@ -256,6 +256,7 @@ struct ceph_inode_info { 
	u32 i_time_warp_seq;



	unsigned i_ceph_flags;

	int i_ordered_count;

	atomic_t i_release_count;

	atomic_t i_complete_count;
@@ -434,14 +435,19 @@ static inline struct inode *ceph_find_inode(struct super_block *sb, 
/*

 * Ceph inode.

 */

#define CEPH_I_DIR_ORDERED	1  /* dentries in dir are ordered */

#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_dir_set_complete(struct ceph_inode_info *ci,

					   int release_count)

					   int release_count, int ordered_count)

{

	atomic_set(&ci->i_complete_count, release_count);

	if (ci->i_ordered_count == ordered_count)

		ci->i_ceph_flags |= CEPH_I_DIR_ORDERED;

	else

		ci->i_ceph_flags &= ~CEPH_I_DIR_ORDERED;

}



static inline void __ceph_dir_clear_complete(struct ceph_inode_info *ci)
@@ -455,16 +461,35 @@ static inline bool __ceph_dir_is_complete(struct ceph_inode_info *ci) 
		atomic_read(&ci->i_release_count);

}



static inline bool __ceph_dir_is_complete_ordered(struct ceph_inode_info *ci)

{

	return __ceph_dir_is_complete(ci) &&

		(ci->i_ceph_flags & CEPH_I_DIR_ORDERED);

}



static inline void ceph_dir_clear_complete(struct inode *inode)

{

	__ceph_dir_clear_complete(ceph_inode(inode));

}



static inline bool ceph_dir_is_complete(struct inode *inode)

static inline void ceph_dir_clear_ordered(struct inode *inode)

{

	return __ceph_dir_is_complete(ceph_inode(inode));

	struct ceph_inode_info *ci = ceph_inode(inode);

	spin_lock(&ci->i_ceph_lock);

	ci->i_ordered_count++;

	ci->i_ceph_flags &= ~CEPH_I_DIR_ORDERED;

	spin_unlock(&ci->i_ceph_lock);

}



static inline bool ceph_dir_is_complete_ordered(struct inode *inode)

{

	struct ceph_inode_info *ci = ceph_inode(inode);

	bool ret;

	spin_lock(&ci->i_ceph_lock);

	ret = __ceph_dir_is_complete_ordered(ci);

	spin_unlock(&ci->i_ceph_lock);

	return ret;

}



/* find a specific frag @f */

extern struct ceph_inode_frag *__ceph_find_frag(struct ceph_inode_info *ci,
@@ -580,6 +605,7 @@ struct ceph_file_info { 
	char *last_name;       /* last entry in previous chunk */

	struct dentry *dentry; /* next dentry (for dcache readdir) */

	int dir_release_count;

	int dir_ordered_count;



	/* used for -o dirstat read() on directory thing */

	char *dir_info;