Merge tag 'zonefs-5.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/dlemoal/zonefs

Pull zonefs updates from Damien Le Moal:
 "This improves zonefs open sequential file accounting and adds
  accounting for active sequential files to allow the user to handle the
  maximum number of active zones of an NVMe ZNS drive.

  sysfs attributes for both open and active sequential files are also
  added to facilitate access to this information from applications
  without resorting to inspecting the block device limits"

* tag 'zonefs-5.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/dlemoal/zonefs:
  documentation: zonefs: Document sysfs attributes
  documentation: zonefs: Cleanup the mount options section
  zonefs: Add active seq file accounting
  zonefs: Export open zone resource information through sysfs
  zonefs: Always do seq file write open accounting
  zonefs: Rename super block information fields
  zonefs: Fix management of open zones
  zonefs: Clear inode information flags on inode creation

1 files changed, 138 insertions, 48 deletions

diff --git a/fs/zonefs/super.c b/fs/zonefs/super.c
index 82da583da17b..b3b0b71fdf6c 100644
--- a/fs/zonefs/super.c
+++ b/fs/zonefs/super.c
@@ -27,6 +27,39 @@
 #define CREATE_TRACE_POINTS
 #include "trace.h"
 
+/*
+ * Manage the active zone count. Called with zi->i_truncate_mutex held.
+ */
+static void zonefs_account_active(struct inode *inode)
+{
+	struct zonefs_sb_info *sbi = ZONEFS_SB(inode->i_sb);
+	struct zonefs_inode_info *zi = ZONEFS_I(inode);
+
+	lockdep_assert_held(&zi->i_truncate_mutex);
+
+	if (zi->i_ztype != ZONEFS_ZTYPE_SEQ)
+		return;
+
+	/*
+	 * If the zone is active, that is, if it is explicitly open or
+	 * partially written, check if it was already accounted as active.
+	 */
+	if ((zi->i_flags & ZONEFS_ZONE_OPEN) ||
+	    (zi->i_wpoffset > 0 && zi->i_wpoffset < zi->i_max_size)) {
+		if (!(zi->i_flags & ZONEFS_ZONE_ACTIVE)) {
+			zi->i_flags |= ZONEFS_ZONE_ACTIVE;
+			atomic_inc(&sbi->s_active_seq_files);
+		}
+		return;
+	}
+
+	/* The zone is not active. If it was, update the active count */
+	if (zi->i_flags & ZONEFS_ZONE_ACTIVE) {
+		zi->i_flags &= ~ZONEFS_ZONE_ACTIVE;
+		atomic_dec(&sbi->s_active_seq_files);
+	}
+}
+
 static inline int zonefs_zone_mgmt(struct inode *inode,
 				   enum req_opf op)
 {
@@ -68,8 +101,13 @@ static inline void zonefs_i_size_write(struct inode *inode, loff_t isize)
 	 * A full zone is no longer open/active and does not need
 	 * explicit closing.
 	 */
-	if (isize >= zi->i_max_size)
-		zi->i_flags &= ~ZONEFS_ZONE_OPEN;
+	if (isize >= zi->i_max_size) {
+		struct zonefs_sb_info *sbi = ZONEFS_SB(inode->i_sb);
+
+		if (zi->i_flags & ZONEFS_ZONE_ACTIVE)
+			atomic_dec(&sbi->s_active_seq_files);
+		zi->i_flags &= ~(ZONEFS_ZONE_OPEN | ZONEFS_ZONE_ACTIVE);
+	}
 }
 
 static int zonefs_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
@@ -397,6 +435,7 @@ static int zonefs_io_error_cb(struct blk_zone *zone, unsigned int idx,
 	zonefs_update_stats(inode, data_size);
 	zonefs_i_size_write(inode, data_size);
 	zi->i_wpoffset = data_size;
+	zonefs_account_active(inode);
 
 	return 0;
 }
@@ -508,6 +547,7 @@ static int zonefs_file_truncate(struct inode *inode, loff_t isize)
 	zonefs_update_stats(inode, isize);
 	truncate_setsize(inode, isize);
 	zi->i_wpoffset = isize;
+	zonefs_account_active(inode);
 
 unlock:
 	mutex_unlock(&zi->i_truncate_mutex);
@@ -865,8 +905,15 @@ static ssize_t zonefs_file_dio_write(struct kiocb *iocb, struct iov_iter *from)
 	    (ret > 0 || ret == -EIOCBQUEUED)) {
 		if (ret > 0)
 			count = ret;
+
+		/*
+		 * Update the zone write pointer offset assuming the write
+		 * operation succeeded. If it did not, the error recovery path
+		 * will correct it. Also do active seq file accounting.
+		 */
 		mutex_lock(&zi->i_truncate_mutex);
 		zi->i_wpoffset += count;
+		zonefs_account_active(inode);
 		mutex_unlock(&zi->i_truncate_mutex);
 	}
 
@@ -1008,13 +1055,13 @@ inode_unlock:
 	return ret;
 }
 
-static inline bool zonefs_file_use_exp_open(struct inode *inode, struct file *file)
+/*
+ * Write open accounting is done only for sequential files.
+ */
+static inline bool zonefs_seq_file_need_wro(struct inode *inode,
+					    struct file *file)
 {
 	struct zonefs_inode_info *zi = ZONEFS_I(inode);
-	struct zonefs_sb_info *sbi = ZONEFS_SB(inode->i_sb);
-
-	if (!(sbi->s_mount_opts & ZONEFS_MNTOPT_EXPLICIT_OPEN))
-		return false;
 
 	if (zi->i_ztype != ZONEFS_ZTYPE_SEQ)
 		return false;
@@ -1025,28 +1072,34 @@ static inline bool zonefs_file_use_exp_open(struct inode *inode, struct file *fi
 	return true;
 }
 
-static int zonefs_open_zone(struct inode *inode)
+static int zonefs_seq_file_write_open(struct inode *inode)
 {
 	struct zonefs_inode_info *zi = ZONEFS_I(inode);
-	struct zonefs_sb_info *sbi = ZONEFS_SB(inode->i_sb);
 	int ret = 0;
 
 	mutex_lock(&zi->i_truncate_mutex);
 
 	if (!zi->i_wr_refcnt) {
-		if (atomic_inc_return(&sbi->s_open_zones) > sbi->s_max_open_zones) {
-			atomic_dec(&sbi->s_open_zones);
-			ret = -EBUSY;
-			goto unlock;
-		}
+		struct zonefs_sb_info *sbi = ZONEFS_SB(inode->i_sb);
+		unsigned int wro = atomic_inc_return(&sbi->s_wro_seq_files);
 
-		if (i_size_read(inode) < zi->i_max_size) {
-			ret = zonefs_zone_mgmt(inode, REQ_OP_ZONE_OPEN);
-			if (ret) {
-				atomic_dec(&sbi->s_open_zones);
+		if (sbi->s_mount_opts & ZONEFS_MNTOPT_EXPLICIT_OPEN) {
+
+			if (wro > sbi->s_max_wro_seq_files) {
+				atomic_dec(&sbi->s_wro_seq_files);
+				ret = -EBUSY;
 				goto unlock;
 			}
-			zi->i_flags |= ZONEFS_ZONE_OPEN;
+
+			if (i_size_read(inode) < zi->i_max_size) {
+				ret = zonefs_zone_mgmt(inode, REQ_OP_ZONE_OPEN);
+				if (ret) {
+					atomic_dec(&sbi->s_wro_seq_files);
+					goto unlock;
+				}
+				zi->i_flags |= ZONEFS_ZONE_OPEN;
+				zonefs_account_active(inode);
+			}
 		}
 	}
 
@@ -1066,30 +1119,31 @@ static int zonefs_file_open(struct inode *inode, struct file *file)
 	if (ret)
 		return ret;
 
-	if (zonefs_file_use_exp_open(inode, file))
-		return zonefs_open_zone(inode);
+	if (zonefs_seq_file_need_wro(inode, file))
+		return zonefs_seq_file_write_open(inode);
 
 	return 0;
 }
 
-static void zonefs_close_zone(struct inode *inode)
+static void zonefs_seq_file_write_close(struct inode *inode)
 {
 	struct zonefs_inode_info *zi = ZONEFS_I(inode);
+	struct super_block *sb = inode->i_sb;
+	struct zonefs_sb_info *sbi = ZONEFS_SB(sb);
 	int ret = 0;
 
 	mutex_lock(&zi->i_truncate_mutex);
-	zi->i_wr_refcnt--;
-	if (!zi->i_wr_refcnt) {
-		struct zonefs_sb_info *sbi = ZONEFS_SB(inode->i_sb);
-		struct super_block *sb = inode->i_sb;
 
-		/*
-		 * If the file zone is full, it is not open anymore and we only
-		 * need to decrement the open count.
-		 */
-		if (!(zi->i_flags & ZONEFS_ZONE_OPEN))
-			goto dec;
+	zi->i_wr_refcnt--;
+	if (zi->i_wr_refcnt)
+		goto unlock;
 
+	/*
+	 * The file zone may not be open anymore (e.g. the file was truncated to
+	 * its maximum size or it was fully written). For this case, we only
+	 * need to decrement the write open count.
+	 */
+	if (zi->i_flags & ZONEFS_ZONE_OPEN) {
 		ret = zonefs_zone_mgmt(inode, REQ_OP_ZONE_CLOSE);
 		if (ret) {
 			__zonefs_io_error(inode, false);
@@ -1101,14 +1155,23 @@ static void zonefs_close_zone(struct inode *inode)
 			 */
 			if (zi->i_flags & ZONEFS_ZONE_OPEN &&
 			    !(sb->s_flags & SB_RDONLY)) {
-				zonefs_warn(sb, "closing zone failed, remounting filesystem read-only\n");
+				zonefs_warn(sb,
+					"closing zone at %llu failed %d\n",
+					zi->i_zsector, ret);
+				zonefs_warn(sb,
+					"remounting filesystem read-only\n");
 				sb->s_flags |= SB_RDONLY;
 			}
+			goto unlock;
 		}
+
 		zi->i_flags &= ~ZONEFS_ZONE_OPEN;
-dec:
-		atomic_dec(&sbi->s_open_zones);
+		zonefs_account_active(inode);
 	}
+
+	atomic_dec(&sbi->s_wro_seq_files);
+
+unlock:
 	mutex_unlock(&zi->i_truncate_mutex);
 }
 
@@ -1120,8 +1183,8 @@ static int zonefs_file_release(struct inode *inode, struct file *file)
 	 * the zone has gone offline or read-only). Make sure we don't fail the
 	 * close(2) for user-space.
 	 */
-	if (zonefs_file_use_exp_open(inode, file))
-		zonefs_close_zone(inode);
+	if (zonefs_seq_file_need_wro(inode, file))
+		zonefs_seq_file_write_close(inode);
 
 	return 0;
 }
@@ -1310,7 +1373,7 @@ static int zonefs_init_file_inode(struct inode *inode, struct blk_zone *zone,
 	struct super_block *sb = inode->i_sb;
 	struct zonefs_sb_info *sbi = ZONEFS_SB(sb);
 	struct zonefs_inode_info *zi = ZONEFS_I(inode);
-	int ret = 0;
+	int ret;
 
 	inode->i_ino = zone->start >> sbi->s_zone_sectors_shift;
 	inode->i_mode = S_IFREG | sbi->s_perm;
@@ -1336,6 +1399,8 @@ static int zonefs_init_file_inode(struct inode *inode, struct blk_zone *zone,
 	sbi->s_blocks += zi->i_max_size >> sb->s_blocksize_bits;
 	sbi->s_used_blocks += zi->i_wpoffset >> sb->s_blocksize_bits;
 
+	mutex_lock(&zi->i_truncate_mutex);
+
 	/*
 	 * For sequential zones, make sure that any open zone is closed first
 	 * to ensure that the initial number of open zones is 0, in sync with
@@ -1345,12 +1410,17 @@ static int zonefs_init_file_inode(struct inode *inode, struct blk_zone *zone,
 	if (type == ZONEFS_ZTYPE_SEQ &&
 	    (zone->cond == BLK_ZONE_COND_IMP_OPEN ||
 	     zone->cond == BLK_ZONE_COND_EXP_OPEN)) {
-		mutex_lock(&zi->i_truncate_mutex);
 		ret = zonefs_zone_mgmt(inode, REQ_OP_ZONE_CLOSE);
-		mutex_unlock(&zi->i_truncate_mutex);
+		if (ret)
+			goto unlock;
 	}
 
-	return ret;
+	zonefs_account_active(inode);
+
+unlock:
+	mutex_unlock(&zi->i_truncate_mutex);
+
+	return 0;
 }
 
 static struct dentry *zonefs_create_inode(struct dentry *parent,
@@ -1687,14 +1757,18 @@ static int zonefs_fill_super(struct super_block *sb, void *data, int silent)
 	sbi->s_gid = GLOBAL_ROOT_GID;
 	sbi->s_perm = 0640;
 	sbi->s_mount_opts = ZONEFS_MNTOPT_ERRORS_RO;
-	sbi->s_max_open_zones = bdev_max_open_zones(sb->s_bdev);
-	atomic_set(&sbi->s_open_zones, 0);
-	if (!sbi->s_max_open_zones &&
+
+	atomic_set(&sbi->s_wro_seq_files, 0);
+	sbi->s_max_wro_seq_files = bdev_max_open_zones(sb->s_bdev);
+	if (!sbi->s_max_wro_seq_files &&
 	    sbi->s_mount_opts & ZONEFS_MNTOPT_EXPLICIT_OPEN) {
 		zonefs_info(sb, "No open zones limit. Ignoring explicit_open mount option\n");
 		sbi->s_mount_opts &= ~ZONEFS_MNTOPT_EXPLICIT_OPEN;
 	}
 
+	atomic_set(&sbi->s_active_seq_files, 0);
+	sbi->s_max_active_seq_files = bdev_max_active_zones(sb->s_bdev);
+
 	ret = zonefs_read_super(sb);
 	if (ret)
 		return ret;
@@ -1709,6 +1783,10 @@ static int zonefs_fill_super(struct super_block *sb, void *data, int silent)
 	if (ret)
 		goto cleanup;
 
+	ret = zonefs_sysfs_register(sb);
+	if (ret)
+		goto cleanup;
+
 	zonefs_info(sb, "Mounting %u zones",
 		    blkdev_nr_zones(sb->s_bdev->bd_disk));
 
@@ -1754,6 +1832,8 @@ static void zonefs_kill_super(struct super_block *sb)
 
 	if (sb->s_root)
 		d_genocide(sb->s_root);
+
+	zonefs_sysfs_unregister(sb);
 	kill_block_super(sb);
 	kfree(sbi);
 }
@@ -1801,16 +1881,26 @@ static int __init zonefs_init(void)
 		return ret;
 
 	ret = register_filesystem(&zonefs_type);
-	if (ret) {
-		zonefs_destroy_inodecache();
-		return ret;
-	}
+	if (ret)
+		goto destroy_inodecache;
+
+	ret = zonefs_sysfs_init();
+	if (ret)
+		goto unregister_fs;
 
 	return 0;
+
+unregister_fs:
+	unregister_filesystem(&zonefs_type);
+destroy_inodecache:
+	zonefs_destroy_inodecache();
+
+	return ret;
 }
 
 static void __exit zonefs_exit(void)
 {
+	zonefs_sysfs_exit();
 	zonefs_destroy_inodecache();
 	unregister_filesystem(&zonefs_type);
 }