1 files changed, 45 insertions, 20 deletions

diff --git a/fs/nilfs2/the_nilfs.c b/fs/nilfs2/the_nilfs.c
index 2ae2c1bbf6d1..d0bcf744c553 100644
--- a/fs/nilfs2/the_nilfs.c
+++ b/fs/nilfs2/the_nilfs.c
@@ -12,7 +12,6 @@
 #include <linux/slab.h>
 #include <linux/blkdev.h>
 #include <linux/backing-dev.h>
-#include <linux/random.h>
 #include <linux/log2.h>
 #include <linux/crc32.h>
 #include "nilfs.h"
@@ -50,8 +49,8 @@ void nilfs_set_last_segment(struct the_nilfs *nilfs,
  * alloc_nilfs - allocate a nilfs object
  * @sb: super block instance
  *
- * Return Value: On success, pointer to the_nilfs is returned.
- * On error, NULL is returned.
+ * Return: a pointer to the allocated nilfs object on success, or NULL on
+ * failure.
  */
 struct the_nilfs *alloc_nilfs(struct super_block *sb)
 {
@@ -69,7 +68,6 @@ struct the_nilfs *alloc_nilfs(struct super_block *sb)
 	INIT_LIST_HEAD(&nilfs->ns_dirty_files);
 	INIT_LIST_HEAD(&nilfs->ns_gc_inodes);
 	spin_lock_init(&nilfs->ns_inode_lock);
-	spin_lock_init(&nilfs->ns_next_gen_lock);
 	spin_lock_init(&nilfs->ns_last_segment_lock);
 	nilfs->ns_cptree = RB_ROOT;
 	spin_lock_init(&nilfs->ns_cptree_lock);
@@ -167,6 +165,9 @@ static void nilfs_clear_recovery_info(struct nilfs_recovery_info *ri)
  * containing a super root from a given super block, and initializes
  * relevant information on the nilfs object preparatory for log
  * scanning and recovery.
+ *
+ * Return: 0 on success, or %-EINVAL if current segment number is out
+ * of range.
  */
 static int nilfs_store_log_cursor(struct the_nilfs *nilfs,
 				  struct nilfs_super_block *sbp)
@@ -202,8 +203,7 @@ static int nilfs_store_log_cursor(struct the_nilfs *nilfs,
  * exponent information written in @sbp and stores it in @blocksize,
  * or aborts with an error message if it's too large.
  *
- * Return Value: On success, 0 is returned. If the block size is too
- * large, -EINVAL is returned.
+ * Return: 0 on success, or %-EINVAL if the block size is too large.
  */
 static int nilfs_get_blocksize(struct super_block *sb,
 			       struct nilfs_super_block *sbp, int *blocksize)
@@ -228,6 +228,13 @@ static int nilfs_get_blocksize(struct super_block *sb,
  * load_nilfs() searches and load the latest super root,
  * attaches the last segment, and does recovery if needed.
  * The caller must call this exclusively for simultaneous mounts.
+ *
+ * Return: 0 on success, or one of the following negative error codes on
+ * failure:
+ * * %-EINVAL	- No valid segment found.
+ * * %-EIO	- I/O error.
+ * * %-ENOMEM	- Insufficient memory available.
+ * * %-EROFS	- Read only device or RO compat mode (if recovery is required)
  */
 int load_nilfs(struct the_nilfs *nilfs, struct super_block *sb)
 {
@@ -397,6 +404,8 @@ static unsigned long long nilfs_max_size(unsigned int blkbits)
  * nilfs_nrsvsegs - calculate the number of reserved segments
  * @nilfs: nilfs object
  * @nsegs: total number of segments
+ *
+ * Return: Number of reserved segments.
  */
 unsigned long nilfs_nrsvsegs(struct the_nilfs *nilfs, unsigned long nsegs)
 {
@@ -408,6 +417,8 @@ unsigned long nilfs_nrsvsegs(struct the_nilfs *nilfs, unsigned long nsegs)
 /**
  * nilfs_max_segment_count - calculate the maximum number of segments
  * @nilfs: nilfs object
+ *
+ * Return: Maximum number of segments
  */
 static u64 nilfs_max_segment_count(struct the_nilfs *nilfs)
 {
@@ -452,6 +463,12 @@ static int nilfs_store_disk_layout(struct the_nilfs *nilfs,
 	}
 
 	nilfs->ns_first_ino = le32_to_cpu(sbp->s_first_ino);
+	if (nilfs->ns_first_ino < NILFS_USER_INO) {
+		nilfs_err(nilfs->ns_sb,
+			  "too small lower limit for non-reserved inode numbers: %u",
+			  nilfs->ns_first_ino);
+		return -EINVAL;
+	}
 
 	nilfs->ns_blocks_per_segment = le32_to_cpu(sbp->s_blocks_per_segment);
 	if (nilfs->ns_blocks_per_segment < NILFS_SEG_MIN_BLOCKS) {
@@ -534,7 +551,7 @@ static int nilfs_valid_sb(struct nilfs_super_block *sbp)
  * area, or if the parameters themselves are not normal, it is
  * determined to be invalid.
  *
- * Return Value: true if invalid, false if valid.
+ * Return: true if invalid, false if valid.
  */
 static bool nilfs_sb2_bad_offset(struct nilfs_super_block *sbp, u64 offset)
 {
@@ -592,7 +609,7 @@ static int nilfs_load_super_block(struct the_nilfs *nilfs,
 	struct nilfs_super_block **sbp = nilfs->ns_sbp;
 	struct buffer_head **sbh = nilfs->ns_sbh;
 	u64 sb2off, devsize = bdev_nr_bytes(nilfs->ns_bdev);
-	int valid[2], swp = 0;
+	int valid[2], swp = 0, older;
 
 	if (devsize < NILFS_SEG_MIN_BLOCKS * NILFS_MIN_BLOCK_SIZE + 4096) {
 		nilfs_err(sb, "device size too small");
@@ -648,9 +665,25 @@ static int nilfs_load_super_block(struct the_nilfs *nilfs,
 	if (swp)
 		nilfs_swap_super_block(nilfs);
 
+	/*
+	 * Calculate the array index of the older superblock data.
+	 * If one has been dropped, set index 0 pointing to the remaining one,
+	 * otherwise set index 1 pointing to the old one (including if both
+	 * are the same).
+	 *
+	 *  Divided case             valid[0]  valid[1]  swp  ->  older
+	 *  -------------------------------------------------------------
+	 *  Both SBs are invalid        0         0       N/A (Error)
+	 *  SB1 is invalid              0         1       1         0
+	 *  SB2 is invalid              1         0       0         0
+	 *  SB2 is newer                1         1       1         0
+	 *  SB2 is older or the same    1         1       0         1
+	 */
+	older = valid[1] ^ swp;
+
 	nilfs->ns_sbwcount = 0;
 	nilfs->ns_sbwtime = le64_to_cpu(sbp[0]->s_wtime);
-	nilfs->ns_prot_seq = le64_to_cpu(sbp[valid[1] & !swp]->s_last_seq);
+	nilfs->ns_prot_seq = le64_to_cpu(sbp[older]->s_last_seq);
 	*sbpp = sbp[0];
 	return 0;
 }
@@ -659,23 +692,19 @@ static int nilfs_load_super_block(struct the_nilfs *nilfs,
  * init_nilfs - initialize a NILFS instance.
  * @nilfs: the_nilfs structure
  * @sb: super block
- * @data: mount options
  *
  * init_nilfs() performs common initialization per block device (e.g.
  * reading the super block, getting disk layout information, initializing
  * shared fields in the_nilfs).
  *
- * Return Value: On success, 0 is returned. On error, a negative error
- * code is returned.
+ * Return: 0 on success, or a negative error code on failure.
  */
-int init_nilfs(struct the_nilfs *nilfs, struct super_block *sb, char *data)
+int init_nilfs(struct the_nilfs *nilfs, struct super_block *sb)
 {
 	struct nilfs_super_block *sbp;
 	int blocksize;
 	int err;
 
-	down_write(&nilfs->ns_sem);
-
 	blocksize = sb_min_blocksize(sb, NILFS_MIN_BLOCK_SIZE);
 	if (!blocksize) {
 		nilfs_err(sb, "unable to set blocksize");
@@ -686,7 +715,7 @@ int init_nilfs(struct the_nilfs *nilfs, struct super_block *sb, char *data)
 	if (err)
 		goto out;
 
-	err = nilfs_store_magic_and_option(sb, sbp, data);
+	err = nilfs_store_magic(sb, sbp);
 	if (err)
 		goto failed_sbh;
 
@@ -733,9 +762,6 @@ int init_nilfs(struct the_nilfs *nilfs, struct super_block *sb, char *data)
 	nilfs->ns_blocksize_bits = sb->s_blocksize_bits;
 	nilfs->ns_blocksize = blocksize;
 
-	get_random_bytes(&nilfs->ns_next_generation,
-			 sizeof(nilfs->ns_next_generation));
-
 	err = nilfs_store_disk_layout(nilfs, sbp);
 	if (err)
 		goto failed_sbh;
@@ -751,7 +777,6 @@ int init_nilfs(struct the_nilfs *nilfs, struct super_block *sb, char *data)
 	set_nilfs_init(nilfs);
 	err = 0;
  out:
-	up_write(&nilfs->ns_sem);
 	return err;
 
  failed_sbh: