From 606686eeac4550d2212bf3d621a810407ef5e9bf Mon Sep 17 00:00:00 2001 From: Josef Bacik Date: Mon, 4 Jun 2012 14:03:51 -0400 Subject: Btrfs: use rcu to protect device->name Al pointed out that we can just toss out the old name on a device and add a new one arbitrarily, so anybody who uses device->name in printk could possibly use free'd memory. Instead of adding locking around all of this he suggested doing it with RCU, so I've introduced a struct rcu_string that does just that and have gone through and protected all accesses to device->name that aren't under the uuid_mutex with rcu_read_lock(). This protects us and I will use it for dealing with removing the device that we used to mount the file system in a later patch. Thanks, Reviewed-by: David Sterba Signed-off-by: Josef Bacik --- fs/btrfs/ioctl.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) (limited to 'fs/btrfs/ioctl.c') diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index 24b776c08d99..c5254dde1f0f 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -52,6 +52,7 @@ #include "locking.h" #include "inode-map.h" #include "backref.h" +#include "rcu-string.h" /* Mask out flags that are inappropriate for the given type of inode. */ static inline __u32 btrfs_mask_flags(umode_t mode, __u32 flags) @@ -1345,8 +1346,9 @@ static noinline int btrfs_ioctl_resize(struct btrfs_root *root, do_div(new_size, root->sectorsize); new_size *= root->sectorsize; - printk(KERN_INFO "btrfs: new size for %s is %llu\n", - device->name, (unsigned long long)new_size); + printk_in_rcu(KERN_INFO "btrfs: new size for %s is %llu\n", + rcu_str_deref(device->name), + (unsigned long long)new_size); if (new_size > old_size) { trans = btrfs_start_transaction(root, 0); @@ -2264,7 +2266,12 @@ static long btrfs_ioctl_dev_info(struct btrfs_root *root, void __user *arg) di_args->total_bytes = dev->total_bytes; memcpy(di_args->uuid, dev->uuid, sizeof(di_args->uuid)); if (dev->name) { - strncpy(di_args->path, dev->name, sizeof(di_args->path)); + struct rcu_string *name; + + rcu_read_lock(); + name = rcu_dereference(dev->name); + strncpy(di_args->path, name->str, sizeof(di_args->path)); + rcu_read_unlock(); di_args->path[sizeof(di_args->path) - 1] = 0; } else { di_args->path[0] = '\0'; -- cgit v1.2.3 From 6c282eb40ed6f64a51ff447707714df551d85b8e Mon Sep 17 00:00:00 2001 From: Li Zefan Date: Mon, 11 Jun 2012 16:03:35 +0800 Subject: Btrfs: fix defrag regression If a file has 3 small extents: | ext1 | ext2 | ext3 | Running "btrfs fi defrag" will only defrag the last two extents, if those extent mappings hasn't been read into memory from disk. This bug was introduced by commit 17ce6ef8d731af5edac8c39e806db4c7e1f6956f ("Btrfs: add a check to decide if we should defrag the range") The cause is, that commit looked into previous and next extents using lookup_extent_mapping() only. While at it, remove the code that checks the previous extent, since it's sufficient to check the next extent. Signed-off-by: Li Zefan --- fs/btrfs/ioctl.c | 97 ++++++++++++++++++++++++++++---------------------------- 1 file changed, 49 insertions(+), 48 deletions(-) (limited to 'fs/btrfs/ioctl.c') diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index c5254dde1f0f..a98f7d252829 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -786,39 +786,57 @@ none: return -ENOENT; } -/* - * Validaty check of prev em and next em: - * 1) no prev/next em - * 2) prev/next em is an hole/inline extent - */ -static int check_adjacent_extents(struct inode *inode, struct extent_map *em) +static struct extent_map *defrag_lookup_extent(struct inode *inode, u64 start) { struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree; - struct extent_map *prev = NULL, *next = NULL; - int ret = 0; + struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree; + struct extent_map *em; + u64 len = PAGE_CACHE_SIZE; + /* + * hopefully we have this extent in the tree already, try without + * the full extent lock + */ read_lock(&em_tree->lock); - prev = lookup_extent_mapping(em_tree, em->start - 1, (u64)-1); - next = lookup_extent_mapping(em_tree, em->start + em->len, (u64)-1); + em = lookup_extent_mapping(em_tree, start, len); read_unlock(&em_tree->lock); - if ((!prev || prev->block_start >= EXTENT_MAP_LAST_BYTE) && - (!next || next->block_start >= EXTENT_MAP_LAST_BYTE)) - ret = 1; - free_extent_map(prev); - free_extent_map(next); + if (!em) { + /* get the big lock and read metadata off disk */ + lock_extent(io_tree, start, start + len - 1); + em = btrfs_get_extent(inode, NULL, 0, start, len, 0); + unlock_extent(io_tree, start, start + len - 1); + if (IS_ERR(em)) + return NULL; + } + + return em; +} + +static bool defrag_check_next_extent(struct inode *inode, struct extent_map *em) +{ + struct extent_map *next; + bool ret = true; + + /* this is the last extent */ + if (em->start + em->len >= i_size_read(inode)) + return false; + + next = defrag_lookup_extent(inode, em->start + em->len); + if (!next || next->block_start >= EXTENT_MAP_LAST_BYTE) + ret = false; + + free_extent_map(next); return ret; } -static int should_defrag_range(struct inode *inode, u64 start, u64 len, - int thresh, u64 *last_len, u64 *skip, - u64 *defrag_end) +static int should_defrag_range(struct inode *inode, u64 start, int thresh, + u64 *last_len, u64 *skip, u64 *defrag_end) { - struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree; - struct extent_map *em = NULL; - struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree; + struct extent_map *em; int ret = 1; + bool next_mergeable = true; /* * make sure that once we start defragging an extent, we keep on @@ -829,23 +847,9 @@ static int should_defrag_range(struct inode *inode, u64 start, u64 len, *skip = 0; - /* - * hopefully we have this extent in the tree already, try without - * the full extent lock - */ - read_lock(&em_tree->lock); - em = lookup_extent_mapping(em_tree, start, len); - read_unlock(&em_tree->lock); - - if (!em) { - /* get the big lock and read metadata off disk */ - lock_extent(io_tree, start, start + len - 1); - em = btrfs_get_extent(inode, NULL, 0, start, len, 0); - unlock_extent(io_tree, start, start + len - 1); - - if (IS_ERR(em)) - return 0; - } + em = defrag_lookup_extent(inode, start); + if (!em) + return 0; /* this will cover holes, and inline extents */ if (em->block_start >= EXTENT_MAP_LAST_BYTE) { @@ -853,18 +857,15 @@ static int should_defrag_range(struct inode *inode, u64 start, u64 len, goto out; } - /* If we have nothing to merge with us, just skip. */ - if (check_adjacent_extents(inode, em)) { - ret = 0; - goto out; - } + next_mergeable = defrag_check_next_extent(inode, em); /* - * we hit a real extent, if it is big don't bother defragging it again + * we hit a real extent, if it is big or the next extent is not a + * real extent, don't bother defragging it */ - if ((*last_len == 0 || *last_len >= thresh) && em->len >= thresh) + if ((*last_len == 0 || *last_len >= thresh) && + (em->len >= thresh || !next_mergeable)) ret = 0; - out: /* * last_len ends up being a counter of how many bytes we've defragged. @@ -1143,8 +1144,8 @@ int btrfs_defrag_file(struct inode *inode, struct file *file, break; if (!should_defrag_range(inode, (u64)i << PAGE_CACHE_SHIFT, - PAGE_CACHE_SIZE, extent_thresh, - &last_len, &skip, &defrag_end)) { + extent_thresh, &last_len, &skip, + &defrag_end)) { unsigned long next; /* * the should_defrag function tells us how much to skip -- cgit v1.2.3 From 4e42ae1bdcda77fc958a17d7ff4ba5a9c9c207da Mon Sep 17 00:00:00 2001 From: Liu Bo Date: Thu, 14 Jun 2012 02:23:19 -0600 Subject: Btrfs: do not resize a seeding device Seeding devices are not supposed to change any more. Signed-off-by: Liu Bo Signed-off-by: Chris Mason --- fs/btrfs/ioctl.c | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'fs/btrfs/ioctl.c') diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index a98f7d252829..58adbd0356d6 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -1306,6 +1306,13 @@ static noinline int btrfs_ioctl_resize(struct btrfs_root *root, ret = -EINVAL; goto out_free; } + if (device->fs_devices && device->fs_devices->seeding) { + printk(KERN_INFO "btrfs: resizer unable to apply on " + "seeding device %llu\n", devid); + ret = -EINVAL; + goto out_free; + } + if (!strcmp(sizestr, "max")) new_size = device->bdev->bd_inode->i_size; else { -- cgit v1.2.3 From a8c4a33b98b097e69cd1a10672c43d17ad0ffb25 Mon Sep 17 00:00:00 2001 From: Chris Mason Date: Fri, 15 Jun 2012 20:07:17 -0400 Subject: Btrfs: cast devid to unsigned long long for printk %llu Avoid warning in 32 bit machines Signed-off-by: Chris Mason --- fs/btrfs/ioctl.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'fs/btrfs/ioctl.c') diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index 58adbd0356d6..0e92e5763005 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -1308,7 +1308,8 @@ static noinline int btrfs_ioctl_resize(struct btrfs_root *root, } if (device->fs_devices && device->fs_devices->seeding) { printk(KERN_INFO "btrfs: resizer unable to apply on " - "seeding device %llu\n", devid); + "seeding device %llu\n", + (unsigned long long)devid); ret = -EINVAL; goto out_free; } -- cgit v1.2.3