hfsplus_sync_fs always updates volume header information to disk with every
sync. This causes problem for systems trying to monitor disk activity to
switch them to low power state. Also hfsplus_sync_fs is explicitly called
from mount/unmount, which is unnecessary. During mount/unmount we only want
to set/clear volume dirty sate.
Signed-off-by: Sougata Santra <sougata@xxxxxxxxxx>
---
fs/hfsplus/super.c | 101 +++++++++++++++++++++++++++++++++++++++++------------
1 file changed, 79 insertions(+), 22 deletions(-)
diff --git a/fs/hfsplus/super.c b/fs/hfsplus/super.c
index 4cf2024..5cacb06 100644
--- a/fs/hfsplus/super.c
+++ b/fs/hfsplus/super.c
@@ -170,12 +170,61 @@ static void hfsplus_evict_inode(struct inode *inode)
}
}
+/*
+ * Helper to sync volume header state to disk. Caller must acquire
+ * volume header mutex (vh_mutex).
+ */
+static int hfsplus_sync_volume_header_locked(struct super_block *sb)
+{
+ struct hfsplus_sb_info *sbi = HFSPLUS_SB(sb);
+ int write_backup = 0;
+ int error = 0;
+
+ if (test_and_clear_bit(HFSPLUS_SB_WRITEBACKUP, &sbi->flags)) {
+ memcpy(sbi->s_backup_vhdr, sbi->s_vhdr, sizeof(*sbi->s_vhdr));
+ write_backup = 1;
+ }
+
+ error = hfsplus_submit_bio(sb,
+ sbi->part_start + HFSPLUS_VOLHEAD_SECTOR,
+ sbi->s_vhdr_buf, NULL, WRITE_SYNC);
+
+ if (error || !write_backup)
+ goto out;
+
+ error = hfsplus_submit_bio(sb,
+ sbi->part_start + sbi->sect_count - 2,
+ sbi->s_backup_vhdr_buf, NULL, WRITE_SYNC);
+out:
+ return error;
+}
+
+/* Sync dirty/clean volume header state to disk. */
+static int hfsplus_sync_volume_header(struct super_block *sb)
+{
+ struct hfsplus_sb_info *sbi = HFSPLUS_SB(sb);
+ int error = 0;
+
+ hfs_dbg(SUPER, "hfsplus_sync_volume_header\n");
+
+ mutex_lock(&sbi->vh_mutex);
+ error = hfsplus_sync_volume_header_locked(sb);
+ mutex_unlock(&sbi->vh_mutex);
+
+ if (!error && !test_bit(HFSPLUS_SB_NOBARRIER, &sbi->flags))
+ blkdev_issue_flush(sb->s_bdev, GFP_KERNEL, NULL);
+
+ return error;
+}
+
static int hfsplus_sync_fs(struct super_block *sb, int wait)
{
struct hfsplus_sb_info *sbi = HFSPLUS_SB(sb);
struct hfsplus_vh *vhdr = sbi->s_vhdr;
- int write_backup = 0;
+ int write_header = 0;
int error, error2;
+ u32 free_blocks, next_cnid;
+ u32 folder_count, file_count;
if (!wait)
return 0;
@@ -196,7 +245,8 @@ static int hfsplus_sync_fs(struct super_block *sb, int wait)
error = error2;
if (sbi->attr_tree) {
error2 =
- filemap_write_and_wait(sbi->attr_tree->inode->i_mapping);
+ filemap_write_and_wait(
+ sbi->attr_tree->inode->i_mapping);
if (!error)
error = error2;
}
@@ -206,34 +256,41 @@ static int hfsplus_sync_fs(struct super_block *sb, int wait)
mutex_lock(&sbi->vh_mutex);
mutex_lock(&sbi->alloc_mutex);
- vhdr->free_blocks = cpu_to_be32(sbi->free_blocks);
- vhdr->next_cnid = cpu_to_be32(sbi->next_cnid);
- vhdr->folder_count = cpu_to_be32(sbi->folder_count);
- vhdr->file_count = cpu_to_be32(sbi->file_count);
- if (test_and_clear_bit(HFSPLUS_SB_WRITEBACKUP, &sbi->flags)) {
- memcpy(sbi->s_backup_vhdr, sbi->s_vhdr, sizeof(*sbi->s_vhdr));
- write_backup = 1;
+ free_blocks = cpu_to_be32(sbi->free_blocks);
+ next_cnid = cpu_to_be32(sbi->next_cnid);
+ folder_count = cpu_to_be32(sbi->folder_count);
+ file_count = cpu_to_be32(sbi->file_count);
+
+ /* Check if some attribute of volume header has changed. */
+ if (vhdr->free_blocks != free_blocks ||
+ vhdr->next_cnid != next_cnid ||
+ vhdr->folder_count != folder_count ||
+ vhdr->file_count != file_count) {
+ vhdr->free_blocks = free_blocks;
+ vhdr->next_cnid = next_cnid;
+ vhdr->folder_count = folder_count;
+ vhdr->file_count = file_count;
+ write_header = 1;
}
+ /*
+ * Write volume header only when something has changed. Also there
+ * is no need to write backup volume header if nothing has changed
+ * in the the volume header itself.
+ */
+ if (!write_header)
+ goto out;
- error2 = hfsplus_submit_bio(sb,
- sbi->part_start + HFSPLUS_VOLHEAD_SECTOR,
- sbi->s_vhdr_buf, NULL, WRITE_SYNC);
+ error2 = hfsplus_sync_volume_header_locked(sb);
if (!error)
error = error2;
- if (!write_backup)
- goto out;
- error2 = hfsplus_submit_bio(sb,
- sbi->part_start + sbi->sect_count - 2,
- sbi->s_backup_vhdr_buf, NULL, WRITE_SYNC);
- if (!error)
- error2 = error;
out:
mutex_unlock(&sbi->alloc_mutex);
mutex_unlock(&sbi->vh_mutex);
- if (!test_bit(HFSPLUS_SB_NOBARRIER, &sbi->flags))
+ if (write_header && !error &&
+ !test_bit(HFSPLUS_SB_NOBARRIER, &sbi->flags))
blkdev_issue_flush(sb->s_bdev, GFP_KERNEL, NULL);
return error;
@@ -287,7 +344,7 @@ static void hfsplus_put_super(struct super_block *sb)
vhdr->attributes |= cpu_to_be32(HFSPLUS_VOL_UNMNT);
vhdr->attributes &= cpu_to_be32(~HFSPLUS_VOL_INCNSTNT);
- hfsplus_sync_fs(sb, 1);
+ hfsplus_sync_volume_header(sb);
}
hfs_btree_close(sbi->attr_tree);
@@ -539,7 +596,7 @@ static int hfsplus_fill_super(struct super_block *sb, void *data, int silent)
be32_add_cpu(&vhdr->write_count, 1);
vhdr->attributes &= cpu_to_be32(~HFSPLUS_VOL_UNMNT);
vhdr->attributes |= cpu_to_be32(HFSPLUS_VOL_INCNSTNT);
- hfsplus_sync_fs(sb, 1);
+ hfsplus_sync_volume_header(sb);
if (!sbi->hidden_dir) {
mutex_lock(&sbi->vh_mutex);
--
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