diff options
Diffstat (limited to 'fs/block_dev.c')
| -rw-r--r-- | fs/block_dev.c | 113 |
1 files changed, 67 insertions, 46 deletions
diff --git a/fs/block_dev.c b/fs/block_dev.c index 7346c96..50e8c85 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -172,9 +172,8 @@ blkdev_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov, struct file *file = iocb->ki_filp; struct inode *inode = file->f_mapping->host; - return blockdev_direct_IO_no_locking_newtrunc(rw, iocb, inode, - I_BDEV(inode), iov, offset, nr_segs, - blkdev_get_blocks, NULL); + return __blockdev_direct_IO(rw, iocb, inode, I_BDEV(inode), iov, offset, + nr_segs, blkdev_get_blocks, NULL, NULL, 0); } int __sync_blockdev(struct block_device *bdev, int wait) @@ -309,9 +308,8 @@ static int blkdev_write_begin(struct file *file, struct address_space *mapping, loff_t pos, unsigned len, unsigned flags, struct page **pagep, void **fsdata) { - *pagep = NULL; - return block_write_begin_newtrunc(file, mapping, pos, len, flags, - pagep, fsdata, blkdev_get_block); + return block_write_begin(mapping, pos, len, flags, pagep, + blkdev_get_block); } static int blkdev_write_end(struct file *file, struct address_space *mapping, @@ -428,10 +426,13 @@ static inline void __bd_forget(struct inode *inode) inode->i_mapping = &inode->i_data; } -static void bdev_clear_inode(struct inode *inode) +static void bdev_evict_inode(struct inode *inode) { struct block_device *bdev = &BDEV_I(inode)->bdev; struct list_head *p; + truncate_inode_pages(&inode->i_data, 0); + invalidate_inode_buffers(inode); /* is it needed here? */ + end_writeback(inode); spin_lock(&bdev_lock); while ( (p = bdev->bd_inodes.next) != &bdev->bd_inodes ) { __bd_forget(list_entry(p, struct inode, i_devices)); @@ -445,7 +446,7 @@ static const struct super_operations bdev_sops = { .alloc_inode = bdev_alloc_inode, .destroy_inode = bdev_destroy_inode, .drop_inode = generic_delete_inode, - .clear_inode = bdev_clear_inode, + .evict_inode = bdev_evict_inode, }; static int bd_get_sb(struct file_system_type *fs_type, @@ -681,8 +682,8 @@ retry: if (!bd_may_claim(bdev, whole, holder)) return -EBUSY; - /* if someone else is claiming, wait for it to finish */ - if (whole->bd_claiming && whole->bd_claiming != holder) { + /* if claiming is already in progress, wait for it to finish */ + if (whole->bd_claiming) { wait_queue_head_t *wq = bit_waitqueue(&whole->bd_claiming, 0); DEFINE_WAIT(wait); @@ -706,8 +707,13 @@ retry: * @bdev is about to be opened exclusively. Check @bdev can be opened * exclusively and mark that an exclusive open is in progress. Each * successful call to this function must be matched with a call to - * either bd_claim() or bd_abort_claiming(). If this function - * succeeds, the matching bd_claim() is guaranteed to succeed. + * either bd_finish_claiming() or bd_abort_claiming() (which do not + * fail). + * + * This function is used to gain exclusive access to the block device + * without actually causing other exclusive open attempts to fail. It + * should be used when the open sequence itself requires exclusive + * access but may subsequently fail. * * CONTEXT: * Might sleep. @@ -734,6 +740,7 @@ static struct block_device *bd_start_claiming(struct block_device *bdev, return ERR_PTR(-ENXIO); whole = bdget_disk(disk, 0); + module_put(disk->fops->owner); put_disk(disk); if (!whole) return ERR_PTR(-ENOMEM); @@ -782,15 +789,46 @@ static void bd_abort_claiming(struct block_device *whole, void *holder) __bd_abort_claiming(whole, holder); /* releases bdev_lock */ } +/* increment holders when we have a legitimate claim. requires bdev_lock */ +static void __bd_claim(struct block_device *bdev, struct block_device *whole, + void *holder) +{ + /* note that for a whole device bd_holders + * will be incremented twice, and bd_holder will + * be set to bd_claim before being set to holder + */ + whole->bd_holders++; + whole->bd_holder = bd_claim; + bdev->bd_holders++; + bdev->bd_holder = holder; +} + +/** + * bd_finish_claiming - finish claiming a block device + * @bdev: block device of interest (passed to bd_start_claiming()) + * @whole: whole block device returned by bd_start_claiming() + * @holder: holder trying to claim @bdev + * + * Finish a claiming block started by bd_start_claiming(). + * + * CONTEXT: + * Grabs and releases bdev_lock. + */ +static void bd_finish_claiming(struct block_device *bdev, + struct block_device *whole, void *holder) +{ + spin_lock(&bdev_lock); + BUG_ON(!bd_may_claim(bdev, whole, holder)); + __bd_claim(bdev, whole, holder); + __bd_abort_claiming(whole, holder); /* not actually an abort */ +} + /** * bd_claim - claim a block device * @bdev: block device to claim * @holder: holder trying to claim @bdev * - * Try to claim @bdev which must have been opened successfully. This - * function may be called with or without preceding - * blk_start_claiming(). In the former case, this function is always - * successful and terminates the claiming block. + * Try to claim @bdev which must have been opened successfully. * * CONTEXT: * Might sleep. @@ -806,23 +844,10 @@ int bd_claim(struct block_device *bdev, void *holder) might_sleep(); spin_lock(&bdev_lock); - res = bd_prepare_to_claim(bdev, whole, holder); - if (res == 0) { - /* note that for a whole device bd_holders - * will be incremented twice, and bd_holder will - * be set to bd_claim before being set to holder - */ - whole->bd_holders++; - whole->bd_holder = bd_claim; - bdev->bd_holders++; - bdev->bd_holder = holder; - } - - if (whole->bd_claiming) - __bd_abort_claiming(whole, holder); /* releases bdev_lock */ - else - spin_unlock(&bdev_lock); + if (res == 0) + __bd_claim(bdev, whole, holder); + spin_unlock(&bdev_lock); return res; } @@ -1315,19 +1340,20 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part) /* * hooks: /n/, see "layering violations". */ - ret = devcgroup_inode_permission(bdev->bd_inode, perm); - if (ret != 0) { - bdput(bdev); - return ret; + if (!for_part) { + ret = devcgroup_inode_permission(bdev->bd_inode, perm); + if (ret != 0) { + bdput(bdev); + return ret; + } } - lock_kernel(); restart: ret = -ENXIO; disk = get_gendisk(bdev->bd_dev, &partno); if (!disk) - goto out_unlock_kernel; + goto out; mutex_lock_nested(&bdev->bd_mutex, for_part); if (!bdev->bd_openers) { @@ -1407,7 +1433,6 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part) if (for_part) bdev->bd_part_count++; mutex_unlock(&bdev->bd_mutex); - unlock_kernel(); return 0; out_clear: @@ -1420,9 +1445,7 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part) bdev->bd_contains = NULL; out_unlock_bdev: mutex_unlock(&bdev->bd_mutex); - out_unlock_kernel: - unlock_kernel(); - + out: if (disk) module_put(disk->fops->owner); put_disk(disk); @@ -1476,7 +1499,7 @@ static int blkdev_open(struct inode * inode, struct file * filp) if (whole) { if (res == 0) - BUG_ON(bd_claim(bdev, filp) != 0); + bd_finish_claiming(bdev, whole, filp); else bd_abort_claiming(whole, filp); } @@ -1491,7 +1514,6 @@ static int __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part) struct block_device *victim = NULL; mutex_lock_nested(&bdev->bd_mutex, for_part); - lock_kernel(); if (for_part) bdev->bd_part_count--; @@ -1516,7 +1538,6 @@ static int __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part) victim = bdev->bd_contains; bdev->bd_contains = NULL; } - unlock_kernel(); mutex_unlock(&bdev->bd_mutex); bdput(bdev); if (victim) @@ -1712,7 +1733,7 @@ struct block_device *open_bdev_exclusive(const char *path, fmode_t mode, void *h if ((mode & FMODE_WRITE) && bdev_read_only(bdev)) goto out_blkdev_put; - BUG_ON(bd_claim(bdev, holder) != 0); + bd_finish_claiming(bdev, whole, holder); return bdev; out_blkdev_put: |
