From: "Darrick J. Wong" Subject: [PATCH 7/7] fat: Lock buffer_head during metadata updates Date: Mon, 09 May 2011 16:04:11 -0700 Message-ID: <20110509230411.19566.66436.stgit@elm3c44.beaverton.ibm.com> References: <20110509230318.19566.66202.stgit@elm3c44.beaverton.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Cc: Jens Axboe , "Martin K. Petersen" , Jeff Layton , Dave Chinner , linux-kernel , Dave Hansen , Christoph Hellwig , linux-mm@kvack.org, Chris Mason , Joel Becker , linux-scsi , linux-fsdevel , linux-ext4@vger.kernel.org, Mingming Cao To: Theodore Tso , Jan Kara , Alexander Viro , OGAWA Hirofumi , "Darrick J. Wong" < Return-path: In-Reply-To: <20110509230318.19566.66202.stgit@elm3c44.beaverton.ibm.com> Sender: owner-linux-mm@kvack.org List-Id: linux-ext4.vger.kernel.org In order to stabilize page writes during writeback operations, it is necessary to enforce a rule that writes to memory pages containing metadata cannot happen at the same time that the page is being written to disk. To provide this, lock the buffer_head representing a piece of metadata while updating memory. Signed-off-by: Darrick J. Wong --- fs/fat/dir.c | 14 ++++++++++++++ fs/fat/fatent.c | 12 ++++++++++++ fs/fat/inode.c | 2 ++ fs/fat/misc.c | 2 ++ fs/fat/namei_msdos.c | 4 ++++ fs/fat/namei_vfat.c | 4 ++++ 6 files changed, 38 insertions(+), 0 deletions(-) diff --git a/fs/fat/dir.c b/fs/fat/dir.c index ee42b9e..9efea13 100644 --- a/fs/fat/dir.c +++ b/fs/fat/dir.c @@ -958,11 +958,13 @@ static int __fat_remove_entries(struct inode *dir, loff_t pos, int nr_slots) orig_slots = nr_slots; endp = (struct msdos_dir_entry *)(bh->b_data + sb->s_blocksize); + lock_buffer(bh); while (nr_slots && de < endp) { de->name[0] = DELETED_FLAG; de++; nr_slots--; } + unlock_buffer(bh); mark_buffer_dirty_inode(bh, dir); if (IS_DIRSYNC(dir)) err = sync_dirty_buffer(bh); @@ -992,11 +994,13 @@ int fat_remove_entries(struct inode *dir, struct fat_slot_info *sinfo) sinfo->de = NULL; bh = sinfo->bh; sinfo->bh = NULL; + lock_buffer(bh); while (nr_slots && de >= (struct msdos_dir_entry *)bh->b_data) { de->name[0] = DELETED_FLAG; de--; nr_slots--; } + unlock_buffer(bh); mark_buffer_dirty_inode(bh, dir); if (IS_DIRSYNC(dir)) err = sync_dirty_buffer(bh); @@ -1045,7 +1049,9 @@ static int fat_zeroed_cluster(struct inode *dir, sector_t blknr, int nr_used, err = -ENOMEM; goto error; } + lock_buffer(bhs[n]); memset(bhs[n]->b_data, 0, sb->s_blocksize); + unlock_buffer(bhs[n]); set_buffer_uptodate(bhs[n]); mark_buffer_dirty_inode(bhs[n], dir); @@ -1103,6 +1109,7 @@ int fat_alloc_new_dir(struct inode *dir, struct timespec *ts) fat_time_unix2fat(sbi, ts, &time, &date, &time_cs); de = (struct msdos_dir_entry *)bhs[0]->b_data; + lock_buffer(bhs[0]); /* filling the new directory slots ("." and ".." entries) */ memcpy(de[0].name, MSDOS_DOT, MSDOS_NAME); memcpy(de[1].name, MSDOS_DOTDOT, MSDOS_NAME); @@ -1126,6 +1133,7 @@ int fat_alloc_new_dir(struct inode *dir, struct timespec *ts) de[1].starthi = cpu_to_le16(MSDOS_I(dir)->i_logstart >> 16); de[0].size = de[1].size = 0; memset(de + 2, 0, sb->s_blocksize - 2 * sizeof(*de)); + unlock_buffer(bhs[0]); set_buffer_uptodate(bhs[0]); mark_buffer_dirty_inode(bhs[0], dir); @@ -1185,7 +1193,9 @@ static int fat_add_new_entries(struct inode *dir, void *slots, int nr_slots, /* fill the directory entry */ copy = min(size, sb->s_blocksize); + lock_buffer(bhs[n]); memcpy(bhs[n]->b_data, slots, copy); + unlock_buffer(bhs[n]); slots += copy; size -= copy; set_buffer_uptodate(bhs[n]); @@ -1288,7 +1298,9 @@ found: /* Fill the long name slots. */ for (i = 0; i < long_bhs; i++) { int copy = min_t(int, sb->s_blocksize - offset, size); + lock_buffer(bhs[i]); memcpy(bhs[i]->b_data + offset, slots, copy); + unlock_buffer(bhs[i]); mark_buffer_dirty_inode(bhs[i], dir); offset = 0; slots += copy; @@ -1299,7 +1311,9 @@ found: if (!err && i < nr_bhs) { /* Fill the short name slot. */ int copy = min_t(int, sb->s_blocksize - offset, size); + lock_buffer(bhs[i]); memcpy(bhs[i]->b_data + offset, slots, copy); + unlock_buffer(bhs[i]); mark_buffer_dirty_inode(bhs[i], dir); if (IS_DIRSYNC(dir)) err = sync_dirty_buffer(bhs[i]); diff --git a/fs/fat/fatent.c b/fs/fat/fatent.c index b47d2c9..e49a9dd 100644 --- a/fs/fat/fatent.c +++ b/fs/fat/fatent.c @@ -160,6 +160,9 @@ static void fat12_ent_put(struct fat_entry *fatent, int new) if (new == FAT_ENT_EOF) new = EOF_FAT12; + lock_buffer(fatent->bhs[0]); + if (fatent->nr_bhs == 2) + lock_buffer(fatent->bhs[1]); spin_lock(&fat12_entry_lock); if (fatent->entry & 1) { *ent12_p[0] = (new << 4) | (*ent12_p[0] & 0x0f); @@ -169,6 +172,9 @@ static void fat12_ent_put(struct fat_entry *fatent, int new) *ent12_p[1] = (*ent12_p[1] & 0xf0) | (new >> 8); } spin_unlock(&fat12_entry_lock); + if (fatent->nr_bhs == 2) + unlock_buffer(fatent->bhs[1]); + unlock_buffer(fatent->bhs[0]); mark_buffer_dirty_inode(fatent->bhs[0], fatent->fat_inode); if (fatent->nr_bhs == 2) @@ -180,7 +186,9 @@ static void fat16_ent_put(struct fat_entry *fatent, int new) if (new == FAT_ENT_EOF) new = EOF_FAT16; + lock_buffer(fatent->bhs[0]); *fatent->u.ent16_p = cpu_to_le16(new); + unlock_buffer(fatent->bhs[0]); mark_buffer_dirty_inode(fatent->bhs[0], fatent->fat_inode); } @@ -191,7 +199,9 @@ static void fat32_ent_put(struct fat_entry *fatent, int new) WARN_ON(new & 0xf0000000); new |= le32_to_cpu(*fatent->u.ent32_p) & ~0x0fffffff; + lock_buffer(fatent->bhs[0]); *fatent->u.ent32_p = cpu_to_le32(new); + unlock_buffer(fatent->bhs[0]); mark_buffer_dirty_inode(fatent->bhs[0], fatent->fat_inode); } @@ -382,7 +392,9 @@ static int fat_mirror_bhs(struct super_block *sb, struct buffer_head **bhs, err = -ENOMEM; goto error; } + lock_buffer(c_bh); memcpy(c_bh->b_data, bhs[n]->b_data, sb->s_blocksize); + unlock_buffer(c_bh); set_buffer_uptodate(c_bh); mark_buffer_dirty_inode(c_bh, sbi->fat_inode); if (sb->s_flags & MS_SYNCHRONOUS) diff --git a/fs/fat/inode.c b/fs/fat/inode.c index 8d68690..96da554 100644 --- a/fs/fat/inode.c +++ b/fs/fat/inode.c @@ -623,6 +623,7 @@ retry: "for updating (i_pos %lld)\n", i_pos); return -EIO; } + lock_buffer(bh); spin_lock(&sbi->inode_hash_lock); if (i_pos != MSDOS_I(inode)->i_pos) { spin_unlock(&sbi->inode_hash_lock); @@ -649,6 +650,7 @@ retry: &raw_entry->adate, NULL); } spin_unlock(&sbi->inode_hash_lock); + unlock_buffer(bh); mark_buffer_dirty(bh); err = 0; if (wait) diff --git a/fs/fat/misc.c b/fs/fat/misc.c index 970e682..3386d81 100644 --- a/fs/fat/misc.c +++ b/fs/fat/misc.c @@ -70,10 +70,12 @@ int fat_clusters_flush(struct super_block *sb) le32_to_cpu(fsinfo->signature2), sbi->fsinfo_sector); } else { + lock_buffer(bh); if (sbi->free_clusters != -1) fsinfo->free_clusters = cpu_to_le32(sbi->free_clusters); if (sbi->prev_free != -1) fsinfo->next_cluster = cpu_to_le32(sbi->prev_free); + unlock_buffer(bh); mark_buffer_dirty(bh); } brelse(bh); diff --git a/fs/fat/namei_msdos.c b/fs/fat/namei_msdos.c index 7114990..cb53c8f 100644 --- a/fs/fat/namei_msdos.c +++ b/fs/fat/namei_msdos.c @@ -540,8 +540,10 @@ static int do_msdos_rename(struct inode *old_dir, unsigned char *old_name, if (update_dotdot) { int start = MSDOS_I(new_dir)->i_logstart; + lock_buffer(dotdot_bh); dotdot_de->start = cpu_to_le16(start); dotdot_de->starthi = cpu_to_le16(start >> 16); + unlock_buffer(dotdot_bh); mark_buffer_dirty_inode(dotdot_bh, old_inode); if (IS_DIRSYNC(new_dir)) { err = sync_dirty_buffer(dotdot_bh); @@ -582,8 +584,10 @@ error_dotdot: if (update_dotdot) { int start = MSDOS_I(old_dir)->i_logstart; + lock_buffer(dotdot_bh); dotdot_de->start = cpu_to_le16(start); dotdot_de->starthi = cpu_to_le16(start >> 16); + unlock_buffer(dotdot_bh); mark_buffer_dirty_inode(dotdot_bh, old_inode); corrupt |= sync_dirty_buffer(dotdot_bh); } diff --git a/fs/fat/namei_vfat.c b/fs/fat/namei_vfat.c index adae3fb..f7e43f4 100644 --- a/fs/fat/namei_vfat.c +++ b/fs/fat/namei_vfat.c @@ -978,8 +978,10 @@ static int vfat_rename(struct inode *old_dir, struct dentry *old_dentry, if (update_dotdot) { int start = MSDOS_I(new_dir)->i_logstart; + lock_buffer(dotdot_bh); dotdot_de->start = cpu_to_le16(start); dotdot_de->starthi = cpu_to_le16(start >> 16); + unlock_buffer(dotdot_bh); mark_buffer_dirty_inode(dotdot_bh, old_inode); if (IS_DIRSYNC(new_dir)) { err = sync_dirty_buffer(dotdot_bh); @@ -1022,8 +1024,10 @@ error_dotdot: if (update_dotdot) { int start = MSDOS_I(old_dir)->i_logstart; + lock_buffer(dotdot_bh); dotdot_de->start = cpu_to_le16(start); dotdot_de->starthi = cpu_to_le16(start >> 16); + unlock_buffer(dotdot_bh); mark_buffer_dirty_inode(dotdot_bh, old_inode); corrupt |= sync_dirty_buffer(dotdot_bh); } -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. 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