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Message-id: <001701cf6e40$fab98be0$f02ca3a0$@samsung.com> Date: Tue, 13 May 2014 09:19:17 +0900 From: Namjae Jeon <namjae.jeon@...sung.com> To: Theodore Ts'o <tytso@....edu> Cc: linux-ext4 <linux-ext4@...r.kernel.org>, Lukáš Czerner <lczerner@...hat.com>, Ashish Sangwan <a.sangwan@...sung.com> Subject: [PATCH 1/2] ext4: introduce new i_write_mutex to protect fallocate Introduce new i_write_mutex to protect new writes from coming while doing fallocate operations. Also, get rid of aio_mutex as it is covered by i_write_mutex. Signed-off-by: Namjae Jeon <namjae.jeon@...sung.com> Signed-off-by: Ashish Sangwan <a.sangwan@...sung.com> --- fs/ext4/ext4.h | 6 +++--- fs/ext4/extents.c | 18 +++++++++++++++--- fs/ext4/file.c | 18 +++++++++++------- fs/ext4/inode.c | 7 ++++++- fs/ext4/super.c | 3 +-- 5 files changed, 36 insertions(+), 16 deletions(-) diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h index 6b45afa..77e5705 100644 --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -943,6 +943,9 @@ struct ext4_inode_info { /* Precomputed uuid+inum+igen checksum for seeding inode checksums */ __u32 i_csum_seed; + + /* protects fallocate operations racing with new writes */ + struct mutex i_write_mutex; }; /* @@ -2827,10 +2830,7 @@ static inline void ext4_inode_resume_unlocked_dio(struct inode *inode) #define EXT4_WQ_HASH_SZ 37 #define ext4_ioend_wq(v) (&ext4__ioend_wq[((unsigned long)(v)) %\ EXT4_WQ_HASH_SZ]) -#define ext4_aio_mutex(v) (&ext4__aio_mutex[((unsigned long)(v)) %\ - EXT4_WQ_HASH_SZ]) extern wait_queue_head_t ext4__ioend_wq[EXT4_WQ_HASH_SZ]; -extern struct mutex ext4__aio_mutex[EXT4_WQ_HASH_SZ]; #define EXT4_RESIZING 0 extern int ext4_resize_begin(struct super_block *sb); diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c index 086baa9..5262750 100644 --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -4741,6 +4741,8 @@ static long ext4_zero_range(struct file *file, loff_t offset, if (!S_ISREG(inode->i_mode)) return -EINVAL; + mutex_lock(&EXT4_I(inode)->i_write_mutex); + /* * Write out all dirty pages to avoid race conditions * Then release them. @@ -4748,8 +4750,10 @@ static long ext4_zero_range(struct file *file, loff_t offset, if (mapping->nrpages && mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)) { ret = filemap_write_and_wait_range(mapping, offset, offset + len - 1); - if (ret) + if (ret) { + mutex_unlock(&EXT4_I(inode)->i_write_mutex); return ret; + } } /* @@ -4761,8 +4765,10 @@ static long ext4_zero_range(struct file *file, loff_t offset, start = round_up(offset, 1 << blkbits); end = round_down((offset + len), 1 << blkbits); - if (start < offset || end > offset + len) + if (start < offset || end > offset + len) { + mutex_unlock(&EXT4_I(inode)->i_write_mutex); return -EINVAL; + } partial = (offset + len) & ((1 << blkbits) - 1); lblk = start >> blkbits; @@ -4859,6 +4865,7 @@ out_dio: ext4_inode_resume_unlocked_dio(inode); out_mutex: mutex_unlock(&inode->i_mutex); + mutex_unlock(&EXT4_I(inode)->i_write_mutex); return ret; } @@ -5428,11 +5435,15 @@ int ext4_collapse_range(struct inode *inode, loff_t offset, loff_t len) punch_start = offset >> EXT4_BLOCK_SIZE_BITS(sb); punch_stop = (offset + len) >> EXT4_BLOCK_SIZE_BITS(sb); + mutex_lock(&EXT4_I(inode)->i_write_mutex); + /* Call ext4_force_commit to flush all data in case of data=journal. */ if (ext4_should_journal_data(inode)) { ret = ext4_force_commit(inode->i_sb); - if (ret) + if (ret) { + mutex_unlock(&EXT4_I(inode)->i_write_mutex); return ret; + } } /* @@ -5518,5 +5529,6 @@ out_dio: ext4_inode_resume_unlocked_dio(inode); out_mutex: mutex_unlock(&inode->i_mutex); + mutex_unlock(&EXT4_I(inode)->i_write_mutex); return ret; } diff --git a/fs/ext4/file.c b/fs/ext4/file.c index 708aad7..557b4ac 100644 --- a/fs/ext4/file.c +++ b/fs/ext4/file.c @@ -93,7 +93,7 @@ ext4_file_write_iter(struct kiocb *iocb, struct iov_iter *from) { struct file *file = iocb->ki_filp; struct inode *inode = file_inode(iocb->ki_filp); - struct mutex *aio_mutex = NULL; + bool unaligned_direct_aio = false; struct blk_plug plug; int o_direct = file->f_flags & O_DIRECT; int overwrite = 0; @@ -101,6 +101,8 @@ ext4_file_write_iter(struct kiocb *iocb, struct iov_iter *from) ssize_t ret; loff_t pos = iocb->ki_pos; + mutex_lock(&EXT4_I(inode)->i_write_mutex); + /* * Unaligned direct AIO must be serialized; see comment above * In the case of O_APPEND, assume that we must always serialize @@ -110,8 +112,7 @@ ext4_file_write_iter(struct kiocb *iocb, struct iov_iter *from) !is_sync_kiocb(iocb) && (file->f_flags & O_APPEND || ext4_unaligned_aio(inode, from, pos))) { - aio_mutex = ext4_aio_mutex(inode); - mutex_lock(aio_mutex); + unaligned_direct_aio = true; ext4_unwritten_wait(inode); } @@ -143,8 +144,9 @@ ext4_file_write_iter(struct kiocb *iocb, struct iov_iter *from) iocb->private = &overwrite; /* check whether we do a DIO overwrite or not */ - if (ext4_should_dioread_nolock(inode) && !aio_mutex && - !file->f_mapping->nrpages && pos + length <= i_size_read(inode)) { + if (ext4_should_dioread_nolock(inode) && + !unaligned_direct_aio && !file->f_mapping->nrpages && + pos + length <= i_size_read(inode)) { struct ext4_map_blocks map; unsigned int blkbits = inode->i_blkbits; int err, len; @@ -174,6 +176,8 @@ ext4_file_write_iter(struct kiocb *iocb, struct iov_iter *from) ret = __generic_file_write_iter(iocb, from); mutex_unlock(&inode->i_mutex); + if (!unaligned_direct_aio) + mutex_unlock(&EXT4_I(inode)->i_write_mutex); if (ret > 0) { ssize_t err; @@ -186,8 +190,8 @@ ext4_file_write_iter(struct kiocb *iocb, struct iov_iter *from) blk_finish_plug(&plug); errout: - if (aio_mutex) - mutex_unlock(aio_mutex); + if (unaligned_direct_aio) + mutex_unlock(&EXT4_I(inode)->i_write_mutex); return ret; } diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index b1dc334..d804120 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -3528,6 +3528,8 @@ int ext4_punch_hole(struct inode *inode, loff_t offset, loff_t length) trace_ext4_punch_hole(inode, offset, length, 0); + mutex_lock(&EXT4_I(inode)->i_write_mutex); + /* * Write out all dirty pages to avoid race conditions * Then release them. @@ -3535,8 +3537,10 @@ int ext4_punch_hole(struct inode *inode, loff_t offset, loff_t length) if (mapping->nrpages && mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)) { ret = filemap_write_and_wait_range(mapping, offset, offset + length - 1); - if (ret) + if (ret) { + mutex_unlock(&EXT4_I(inode)->i_write_mutex); return ret; + } } mutex_lock(&inode->i_mutex); @@ -3637,6 +3641,7 @@ out_dio: ext4_inode_resume_unlocked_dio(inode); out_mutex: mutex_unlock(&inode->i_mutex); + mutex_unlock(&EXT4_I(inode)->i_write_mutex); return ret; } diff --git a/fs/ext4/super.c b/fs/ext4/super.c index 1f8cb18..e236c85 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -904,6 +904,7 @@ static struct inode *ext4_alloc_inode(struct super_block *sb) atomic_set(&ei->i_ioend_count, 0); atomic_set(&ei->i_unwritten, 0); INIT_WORK(&ei->i_rsv_conversion_work, ext4_end_io_rsv_work); + mutex_init(&ei->i_write_mutex); return &ei->vfs_inode; } @@ -5505,7 +5506,6 @@ static void ext4_exit_feat_adverts(void) /* Shared across all ext4 file systems */ wait_queue_head_t ext4__ioend_wq[EXT4_WQ_HASH_SZ]; -struct mutex ext4__aio_mutex[EXT4_WQ_HASH_SZ]; static int __init ext4_init_fs(void) { @@ -5518,7 +5518,6 @@ static int __init ext4_init_fs(void) ext4_check_flag_values(); for (i = 0; i < EXT4_WQ_HASH_SZ; i++) { - mutex_init(&ext4__aio_mutex[i]); init_waitqueue_head(&ext4__ioend_wq[i]); } -- 1.7.11-rc0 -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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