- 22 11月, 2010 1 次提交
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由 Josef Bacik 提交于
People kept reporting NFS issues, specifically getting ESTALE alot. I figured out how to reproduce the problem SERVER mkfs.btrfs /dev/sda1 mount /dev/sda1 /mnt/btrfs-test <add /mnt/btrfs-test to /etc/exports> btrfs subvol create /mnt/btrfs-test/foo service nfs start CLIENT mount server:/mnt/btrfs /mnt/test cd /mnt/test/foo ls SERVER echo 3 > /proc/sys/vm/drop_caches CLIENT ls <-- get an ESTALE here This is because the standard way to lookup a name in nfsd is to use readdir, and what it does is do a readdir on the parent directory looking for the inode of the child. So in this case the parent being / and the child being foo. Well subvols all have the same inode number, so doing a readdir of / looking for inode 256 will return '.', which obviously doesn't match foo. So instead we need to have our own .get_name so that we can find the right name. Our .get_name will either lookup the inode backref or the root backref, whichever we're looking for, and return the name we find. Running the above reproducer with this patch results in everything acting the way its supposed to. Thanks, Signed-off-by: NJosef Bacik <josef@redhat.com> Signed-off-by: NChris Mason <chris.mason@oracle.com>
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- 15 3月, 2010 1 次提交
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由 Josef Bacik 提交于
This work is in preperation for being able to set a different root as the default mounting root. There is currently a problem with how we mount subvolumes. We cannot currently mount a subvolume of a subvolume, you can only mount subvolumes/snapshots of the default subvolume. So say you take a snapshot of the default subvolume and call it snap1, and then take a snapshot of snap1 and call it snap2, so now you have / /snap1 /snap1/snap2 as your available volumes. Currently you can only mount / and /snap1, you cannot mount /snap1/snap2. To fix this problem instead of passing subvolid=<name> you must pass in subvolid=<treeid>, where <treeid> is the tree id that gets spit out via the subvolume listing you get from the subvolume listing patches (btrfs filesystem list). This allows us to mount /, /snap1 and /snap1/snap2 as the root volume. In addition to the above, we also now read the default dir item in the tree root to get the root key that it points to. For now this just points at what has always been the default subvolme, but later on I plan to change it to point at whatever root you want to be the new default root, so you can just set the default mount and not have to mount with -o subvolid=<treeid>. I tested this out with the above scenario and it worked perfectly. Thanks, mount -o subvol operates inside the selected subvolid. For example: mount -o subvol=snap1,subvolid=256 /dev/xxx /mnt /mnt will have the snap1 directory for the subvolume with id 256. mount -o subvol=snap /dev/xxx /mnt /mnt will be the snap directory of whatever the default subvolume is. Signed-off-by: NJosef Bacik <josef@redhat.com> Signed-off-by: NChris Mason <chris.mason@oracle.com>
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- 22 9月, 2009 1 次提交
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由 Yan, Zheng 提交于
This patch adds snapshot/subvolume destroy ioctl. A subvolume that isn't being used and doesn't contains links to other subvolumes can be destroyed. Signed-off-by: NYan Zheng <zheng.yan@oracle.com> Signed-off-by: NChris Mason <chris.mason@oracle.com>
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- 10 6月, 2009 1 次提交
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由 Yan Zheng 提交于
This commit introduces a new kind of back reference for btrfs metadata. Once a filesystem has been mounted with this commit, IT WILL NO LONGER BE MOUNTABLE BY OLDER KERNELS. When a tree block in subvolume tree is cow'd, the reference counts of all extents it points to are increased by one. At transaction commit time, the old root of the subvolume is recorded in a "dead root" data structure, and the btree it points to is later walked, dropping reference counts and freeing any blocks where the reference count goes to 0. The increments done during cow and decrements done after commit cancel out, and the walk is a very expensive way to go about freeing the blocks that are no longer referenced by the new btree root. This commit reduces the transaction overhead by avoiding the need for dead root records. When a non-shared tree block is cow'd, we free the old block at once, and the new block inherits old block's references. When a tree block with reference count > 1 is cow'd, we increase the reference counts of all extents the new block points to by one, and decrease the old block's reference count by one. This dead tree avoidance code removes the need to modify the reference counts of lower level extents when a non-shared tree block is cow'd. But we still need to update back ref for all pointers in the block. This is because the location of the block is recorded in the back ref item. We can solve this by introducing a new type of back ref. The new back ref provides information about pointer's key, level and in which tree the pointer lives. This information allow us to find the pointer by searching the tree. The shortcoming of the new back ref is that it only works for pointers in tree blocks referenced by their owner trees. This is mostly a problem for snapshots, where resolving one of these fuzzy back references would be O(number_of_snapshots) and quite slow. The solution used here is to use the fuzzy back references in the common case where a given tree block is only referenced by one root, and use the full back references when multiple roots have a reference on a given block. This commit adds per subvolume red-black tree to keep trace of cached inodes. The red-black tree helps the balancing code to find cached inodes whose inode numbers within a given range. This commit improves the balancing code by introducing several data structures to keep the state of balancing. The most important one is the back ref cache. It caches how the upper level tree blocks are referenced. This greatly reduce the overhead of checking back ref. The improved balancing code scales significantly better with a large number of snapshots. This is a very large commit and was written in a number of pieces. But, they depend heavily on the disk format change and were squashed together to make sure git bisect didn't end up in a bad state wrt space balancing or the format change. Signed-off-by: NYan Zheng <zheng.yan@oracle.com> Signed-off-by: NChris Mason <chris.mason@oracle.com>
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- 06 1月, 2009 1 次提交
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由 Chris Mason 提交于
There were many, most are fixed now. struct-funcs.c generates some warnings but these are bogus. Signed-off-by: NChris Mason <chris.mason@oracle.com>
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- 26 9月, 2008 1 次提交
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由 Chris Mason 提交于
Btrfs had compatibility code for kernels back to 2.6.18. These have been removed, and will be maintained in a separate backport git tree from now on. Signed-off-by: NChris Mason <chris.mason@oracle.com>
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- 25 9月, 2008 5 次提交
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由 Christoph Hellwig 提交于
d_obtain_alias is intended as a tailcall that can pass in errors encoded in the inode pointer if needed, so use it that way instead of duplicating the error handling. Signed-off-by: NChristoph Hellwig <hch@lst.de> Signed-off-by: NChris Mason <chris.mason@oracle.com>
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由 David Woodhouse 提交于
Date: Tue, 19 Aug 2008 22:33:04 +0100 Signed-off-by: NDavid Woodhouse <David.Woodhouse@intel.com> Signed-off-by: NChris Mason <chris.mason@oracle.com>
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由 David Woodhouse 提交于
Date: Tue, 19 Aug 2008 22:20:17 +0100 btrfs_lookup_fs_root() only finds subvol roots which have already been seen and put into the cache. For btrfs_get_dentry() we actually have to go to the medium -- so use btrfs_read_fs_root_no_name() instead. In btrfs_get_parent(), notice when we've hit the root of the subvolume and return the real root instead. Signed-off-by: NDavid Woodhouse <David.Woodhouse@intel.com> Signed-off-by: NChris Mason <chris.mason@oracle.com>
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由 David Woodhouse 提交于
Date: Mon, 18 Aug 2008 22:50:22 +0100 Signed-off-by: NDavid Woodhouse <David.Woodhouse@intel.com> Signed-off-by: NChris Mason <chris.mason@oracle.com>
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由 Balaji Rao 提交于
Date: Mon, 21 Jul 2008 02:01:56 +0530 Here's an implementation of NFS support for btrfs. It relies on the fixes which are going in to 2.6.28 for the NFS readdir/lookup deadlock. This uses the btrfs_iget helper introduced previously. [dwmw2: Tidy up a little, switch to d_obtain_alias() w/compat routine, change fh_type, store parent's root object ID where needed, fix some get_parent() and fs_to_dentry() bugs] Signed-off-by: NBalaji Rao <balajirrao@gmail.com> Signed-off-by: NDavid Woodhouse <David.Woodhouse@intel.com> Signed-off-by: NChris Mason <chris.mason@oracle.com>
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