From 3a3076f4d6e2fa31338a0b007df42a3b32f079e0 Mon Sep 17 00:00:00 2001 From: Josef Bacik Date: Fri, 23 Apr 2010 12:17:17 -0400 Subject: Cleanup generic block based fiemap This cleans up a few of the complaints of __generic_block_fiemap. I've fixed all the typing stuff, used inline functions instead of macros, gotten rid of a couple of variables, and made sure the size and block requests are all block aligned. It also fixes a problem where sometimes FIEMAP_EXTENT_LAST wasn't being set properly. Signed-off-by: Josef Bacik Signed-off-by: Linus Torvalds --- fs/ioctl.c | 92 ++++++++++++++++++++++++++++++++++++-------------------------- 1 file changed, 53 insertions(+), 39 deletions(-) (limited to 'fs/ioctl.c') diff --git a/fs/ioctl.c b/fs/ioctl.c index 6c751106c2e5..7faefb4da939 100644 --- a/fs/ioctl.c +++ b/fs/ioctl.c @@ -228,14 +228,23 @@ static int ioctl_fiemap(struct file *filp, unsigned long arg) #ifdef CONFIG_BLOCK -#define blk_to_logical(inode, blk) (blk << (inode)->i_blkbits) -#define logical_to_blk(inode, offset) (offset >> (inode)->i_blkbits); +static inline sector_t logical_to_blk(struct inode *inode, loff_t offset) +{ + return (offset >> inode->i_blkbits); +} + +static inline loff_t blk_to_logical(struct inode *inode, sector_t blk) +{ + return (blk << inode->i_blkbits); +} /** * __generic_block_fiemap - FIEMAP for block based inodes (no locking) - * @inode - the inode to map - * @arg - the pointer to userspace where we copy everything to - * @get_block - the fs's get_block function + * @inode: the inode to map + * @fieinfo: the fiemap info struct that will be passed back to userspace + * @start: where to start mapping in the inode + * @len: how much space to map + * @get_block: the fs's get_block function * * This does FIEMAP for block based inodes. Basically it will just loop * through get_block until we hit the number of extents we want to map, or we @@ -250,58 +259,63 @@ static int ioctl_fiemap(struct file *filp, unsigned long arg) */ int __generic_block_fiemap(struct inode *inode, - struct fiemap_extent_info *fieinfo, u64 start, - u64 len, get_block_t *get_block) + struct fiemap_extent_info *fieinfo, loff_t start, + loff_t len, get_block_t *get_block) { - struct buffer_head tmp; - unsigned long long start_blk; - long long length = 0, map_len = 0; + struct buffer_head map_bh; + sector_t start_blk, last_blk; + loff_t isize = i_size_read(inode); u64 logical = 0, phys = 0, size = 0; u32 flags = FIEMAP_EXTENT_MERGED; - int ret = 0, past_eof = 0, whole_file = 0; + bool past_eof = false, whole_file = false; + int ret = 0; - if ((ret = fiemap_check_flags(fieinfo, FIEMAP_FLAG_SYNC))) + ret = fiemap_check_flags(fieinfo, FIEMAP_FLAG_SYNC); + if (ret) return ret; - start_blk = logical_to_blk(inode, start); - - length = (long long)min_t(u64, len, i_size_read(inode)); - if (length < len) - whole_file = 1; + /* + * Either the i_mutex or other appropriate locking needs to be held + * since we expect isize to not change at all through the duration of + * this call. + */ + if (len >= isize) { + whole_file = true; + len = isize; + } - map_len = length; + start_blk = logical_to_blk(inode, start); + last_blk = logical_to_blk(inode, start + len - 1); do { /* * we set b_size to the total size we want so it will map as * many contiguous blocks as possible at once */ - memset(&tmp, 0, sizeof(struct buffer_head)); - tmp.b_size = map_len; + memset(&map_bh, 0, sizeof(struct buffer_head)); + map_bh.b_size = len; - ret = get_block(inode, start_blk, &tmp, 0); + ret = get_block(inode, start_blk, &map_bh, 0); if (ret) break; /* HOLE */ - if (!buffer_mapped(&tmp)) { - length -= blk_to_logical(inode, 1); + if (!buffer_mapped(&map_bh)) { start_blk++; /* - * we want to handle the case where there is an + * We want to handle the case where there is an * allocated block at the front of the file, and then * nothing but holes up to the end of the file properly, * to make sure that extent at the front gets properly * marked with FIEMAP_EXTENT_LAST */ if (!past_eof && - blk_to_logical(inode, start_blk) >= - blk_to_logical(inode, 0)+i_size_read(inode)) + blk_to_logical(inode, start_blk) >= isize) past_eof = 1; /* - * first hole after going past the EOF, this is our + * First hole after going past the EOF, this is our * last extent */ if (past_eof && size) { @@ -309,15 +323,18 @@ int __generic_block_fiemap(struct inode *inode, ret = fiemap_fill_next_extent(fieinfo, logical, phys, size, flags); - break; + } else if (size) { + ret = fiemap_fill_next_extent(fieinfo, logical, + phys, size, flags); + size = 0; } /* if we have holes up to/past EOF then we're done */ - if (length <= 0 || past_eof) + if (start_blk > last_blk || past_eof || ret) break; } else { /* - * we have gone over the length of what we wanted to + * We have gone over the length of what we wanted to * map, and it wasn't the entire file, so add the extent * we got last time and exit. * @@ -331,7 +348,7 @@ int __generic_block_fiemap(struct inode *inode, * are good to go, just add the extent to the fieinfo * and break */ - if (length <= 0 && !whole_file) { + if (start_blk > last_blk && !whole_file) { ret = fiemap_fill_next_extent(fieinfo, logical, phys, size, flags); @@ -351,11 +368,10 @@ int __generic_block_fiemap(struct inode *inode, } logical = blk_to_logical(inode, start_blk); - phys = blk_to_logical(inode, tmp.b_blocknr); - size = tmp.b_size; + phys = blk_to_logical(inode, map_bh.b_blocknr); + size = map_bh.b_size; flags = FIEMAP_EXTENT_MERGED; - length -= tmp.b_size; start_blk += logical_to_blk(inode, size); /* @@ -363,15 +379,13 @@ int __generic_block_fiemap(struct inode *inode, * soon as we find a hole that the last extent we found * is marked with FIEMAP_EXTENT_LAST */ - if (!past_eof && - logical+size >= - blk_to_logical(inode, 0)+i_size_read(inode)) - past_eof = 1; + if (!past_eof && logical + size >= isize) + past_eof = true; } cond_resched(); } while (1); - /* if ret is 1 then we just hit the end of the extent array */ + /* If ret is 1 then we just hit the end of the extent array */ if (ret == 1) ret = 0; -- cgit From 18e9e5104fcd9a973ffe3eed3816c87f2a1b6cd2 Mon Sep 17 00:00:00 2001 From: Josef Bacik Date: Tue, 23 Mar 2010 10:34:56 -0400 Subject: Introduce freeze_super and thaw_super for the fsfreeze ioctl Currently the way we do freezing is by passing sb>s_bdev to freeze_bdev and then letting it do all the work. But freezing is more of an fs thing, and doesn't really have much to do with the bdev at all, all the work gets done with the super. In btrfs we do not populate s_bdev, since we can have multiple bdev's for one fs and setting s_bdev makes removing devices from a pool kind of tricky. This means that freezing a btrfs filesystem fails, which causes us to corrupt with things like tux-on-ice which use the fsfreeze mechanism. So instead of populating sb->s_bdev with a random bdev in our pool, I've broken the actual fs freezing stuff into freeze_super and thaw_super. These just take the super_block that we're freezing and does the appropriate work. It's basically just copy and pasted from freeze_bdev. I've then converted freeze_bdev over to use the new super helpers. I've tested this with ext4 and btrfs and verified everything continues to work the same as before. The only new gotcha is multiple calls to the fsfreeze ioctl will return EBUSY if the fs is already frozen. I thought this was a better solution than adding a freeze counter to the super_block, but if everybody hates this idea I'm open to suggestions. Thanks, Signed-off-by: Josef Bacik Signed-off-by: Al Viro --- fs/block_dev.c | 74 ++++++++++---------------------------------- fs/ioctl.c | 15 ++------- fs/super.c | 90 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ include/linux/fs.h | 2 ++ 4 files changed, 110 insertions(+), 71 deletions(-) (limited to 'fs/ioctl.c') diff --git a/fs/block_dev.c b/fs/block_dev.c index 39cb6591d37d..1aba036dcabf 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -245,38 +245,14 @@ struct super_block *freeze_bdev(struct block_device *bdev) sb = get_active_super(bdev); if (!sb) goto out; - down_write(&sb->s_umount); - if (sb->s_flags & MS_RDONLY) { - sb->s_frozen = SB_FREEZE_TRANS; - up_write(&sb->s_umount); + error = freeze_super(sb); + if (error) { + deactivate_super(sb); + bdev->bd_fsfreeze_count--; mutex_unlock(&bdev->bd_fsfreeze_mutex); - return sb; - } - - sb->s_frozen = SB_FREEZE_WRITE; - smp_wmb(); - - sync_filesystem(sb); - - sb->s_frozen = SB_FREEZE_TRANS; - smp_wmb(); - - sync_blockdev(sb->s_bdev); - - if (sb->s_op->freeze_fs) { - error = sb->s_op->freeze_fs(sb); - if (error) { - printk(KERN_ERR - "VFS:Filesystem freeze failed\n"); - sb->s_frozen = SB_UNFROZEN; - deactivate_locked_super(sb); - bdev->bd_fsfreeze_count--; - mutex_unlock(&bdev->bd_fsfreeze_mutex); - return ERR_PTR(error); - } + return ERR_PTR(error); } - up_write(&sb->s_umount); - + deactivate_super(sb); out: sync_blockdev(bdev); mutex_unlock(&bdev->bd_fsfreeze_mutex); @@ -297,40 +273,22 @@ int thaw_bdev(struct block_device *bdev, struct super_block *sb) mutex_lock(&bdev->bd_fsfreeze_mutex); if (!bdev->bd_fsfreeze_count) - goto out_unlock; + goto out; error = 0; if (--bdev->bd_fsfreeze_count > 0) - goto out_unlock; + goto out; if (!sb) - goto out_unlock; - - BUG_ON(sb->s_bdev != bdev); - down_write(&sb->s_umount); - if (sb->s_flags & MS_RDONLY) - goto out_unfrozen; - - if (sb->s_op->unfreeze_fs) { - error = sb->s_op->unfreeze_fs(sb); - if (error) { - printk(KERN_ERR - "VFS:Filesystem thaw failed\n"); - sb->s_frozen = SB_FREEZE_TRANS; - bdev->bd_fsfreeze_count++; - mutex_unlock(&bdev->bd_fsfreeze_mutex); - return error; - } - } - -out_unfrozen: - sb->s_frozen = SB_UNFROZEN; - smp_wmb(); - wake_up(&sb->s_wait_unfrozen); + goto out; - if (sb) - deactivate_locked_super(sb); -out_unlock: + error = thaw_super(sb); + if (error) { + bdev->bd_fsfreeze_count++; + mutex_unlock(&bdev->bd_fsfreeze_mutex); + return error; + } +out: mutex_unlock(&bdev->bd_fsfreeze_mutex); return 0; } diff --git a/fs/ioctl.c b/fs/ioctl.c index 7faefb4da939..2d140a713861 100644 --- a/fs/ioctl.c +++ b/fs/ioctl.c @@ -525,15 +525,8 @@ static int ioctl_fsfreeze(struct file *filp) if (sb->s_op->freeze_fs == NULL) return -EOPNOTSUPP; - /* If a blockdevice-backed filesystem isn't specified, return. */ - if (sb->s_bdev == NULL) - return -EINVAL; - /* Freeze */ - sb = freeze_bdev(sb->s_bdev); - if (IS_ERR(sb)) - return PTR_ERR(sb); - return 0; + return freeze_super(sb); } static int ioctl_fsthaw(struct file *filp) @@ -543,12 +536,8 @@ static int ioctl_fsthaw(struct file *filp) if (!capable(CAP_SYS_ADMIN)) return -EPERM; - /* If a blockdevice-backed filesystem isn't specified, return EINVAL. */ - if (sb->s_bdev == NULL) - return -EINVAL; - /* Thaw */ - return thaw_bdev(sb->s_bdev, sb); + return thaw_super(sb); } /* diff --git a/fs/super.c b/fs/super.c index c248ac6a1a21..89afca5055ab 100644 --- a/fs/super.c +++ b/fs/super.c @@ -944,6 +944,96 @@ out: EXPORT_SYMBOL_GPL(vfs_kern_mount); +/** + * freeze_super -- lock the filesystem and force it into a consistent state + * @super: the super to lock + * + * Syncs the super to make sure the filesystem is consistent and calls the fs's + * freeze_fs. Subsequent calls to this without first thawing the fs will return + * -EBUSY. + */ +int freeze_super(struct super_block *sb) +{ + int ret; + + atomic_inc(&sb->s_active); + down_write(&sb->s_umount); + if (sb->s_frozen) { + deactivate_locked_super(sb); + return -EBUSY; + } + + if (sb->s_flags & MS_RDONLY) { + sb->s_frozen = SB_FREEZE_TRANS; + smp_wmb(); + up_write(&sb->s_umount); + return 0; + } + + sb->s_frozen = SB_FREEZE_WRITE; + smp_wmb(); + + sync_filesystem(sb); + + sb->s_frozen = SB_FREEZE_TRANS; + smp_wmb(); + + sync_blockdev(sb->s_bdev); + if (sb->s_op->freeze_fs) { + ret = sb->s_op->freeze_fs(sb); + if (ret) { + printk(KERN_ERR + "VFS:Filesystem freeze failed\n"); + sb->s_frozen = SB_UNFROZEN; + deactivate_locked_super(sb); + return ret; + } + } + up_write(&sb->s_umount); + return 0; +} +EXPORT_SYMBOL(freeze_super); + +/** + * thaw_super -- unlock filesystem + * @sb: the super to thaw + * + * Unlocks the filesystem and marks it writeable again after freeze_super(). + */ +int thaw_super(struct super_block *sb) +{ + int error; + + down_write(&sb->s_umount); + if (sb->s_frozen == SB_UNFROZEN) { + up_write(&sb->s_umount); + return -EINVAL; + } + + if (sb->s_flags & MS_RDONLY) + goto out; + + if (sb->s_op->unfreeze_fs) { + error = sb->s_op->unfreeze_fs(sb); + if (error) { + printk(KERN_ERR + "VFS:Filesystem thaw failed\n"); + sb->s_frozen = SB_FREEZE_TRANS; + up_write(&sb->s_umount); + return error; + } + } + +out: + sb->s_frozen = SB_UNFROZEN; + smp_wmb(); + wake_up(&sb->s_wait_unfrozen); + deactivate_locked_super(sb); + + return 0; +} +EXPORT_SYMBOL(thaw_super); + static struct vfsmount *fs_set_subtype(struct vfsmount *mnt, const char *fstype) { int err; diff --git a/include/linux/fs.h b/include/linux/fs.h index eeb04ba17b63..d51256bc6328 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1797,6 +1797,8 @@ extern void drop_collected_mounts(struct vfsmount *); extern int iterate_mounts(int (*)(struct vfsmount *, void *), void *, struct vfsmount *); extern int vfs_statfs(struct dentry *, struct kstatfs *); +extern int freeze_super(struct super_block *super); +extern int thaw_super(struct super_block *super); extern int current_umask(void); -- cgit