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path: root/fs/btrfs/print-tree.c
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2020-10-07btrfs: pretty print leaked root nameJosef Bacik1-0/+38
I'm a actual human being so am incapable of converting u64 to s64 in my head, so add a helper to get the pretty name of a root objectid and use that helper to spit out the name for any special roots for leaked roots, so I don't have to scratch my head and figure out which root I messed up the refs for. Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2020-09-07btrfs: require only sector size alignment for parent eb bytenrQu Wenruo1-5/+7
[BUG] A completely sane converted fs will cause kernel warning at balance time: [ 1557.188633] BTRFS info (device sda7): relocating block group 8162107392 flags data [ 1563.358078] BTRFS info (device sda7): found 11722 extents [ 1563.358277] BTRFS info (device sda7): leaf 7989321728 gen 95 total ptrs 213 free space 3458 owner 2 [ 1563.358280] item 0 key (7984947200 169 0) itemoff 16250 itemsize 33 [ 1563.358281] extent refs 1 gen 90 flags 2 [ 1563.358282] ref#0: tree block backref root 4 [ 1563.358285] item 1 key (7985602560 169 0) itemoff 16217 itemsize 33 [ 1563.358286] extent refs 1 gen 93 flags 258 [ 1563.358287] ref#0: shared block backref parent 7985602560 [ 1563.358288] (parent 7985602560 is NOT ALIGNED to nodesize 16384) [ 1563.358290] item 2 key (7985635328 169 0) itemoff 16184 itemsize 33 ... [ 1563.358995] BTRFS error (device sda7): eb 7989321728 invalid extent inline ref type 182 [ 1563.358996] ------------[ cut here ]------------ [ 1563.359005] WARNING: CPU: 14 PID: 2930 at 0xffffffff9f231766 Then with transaction abort, and obviously failed to balance the fs. [CAUSE] That mentioned inline ref type 182 is completely sane, it's BTRFS_SHARED_BLOCK_REF_KEY, it's some extra check making kernel to believe it's invalid. Commit 64ecdb647ddb ("Btrfs: add one more sanity check for shared ref type") introduced extra checks for backref type. One of the requirement is, parent bytenr must be aligned to node size, which is not correct. One example is like this: 0 1G 1G+4K 2G 2G+4K | |///////////////////|//| <- A chunk starts at 1G+4K | | <- A tree block get reserved at bytenr 1G+4K Then we have a valid tree block at bytenr 1G+4K, but not aligned to nodesize (16K). Such chunk is not ideal, but current kernel can handle it pretty well. We may warn about such tree block in the future, but should not reject them. [FIX] Change the alignment requirement from node size alignment to sector size alignment. Also, to make our lives a little easier, also output @iref when btrfs_get_extent_inline_ref_type() failed, so we can locate the item easier. Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=205475 Fixes: 64ecdb647ddb ("Btrfs: add one more sanity check for shared ref type") CC: stable@vger.kernel.org # 4.14+ Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Qu Wenruo <wqu@suse.com> [ update comments and messages ] Signed-off-by: David Sterba <dsterba@suse.com>
2020-01-20btrfs: Remove unneeded semicolonzhengbin1-1/+1
Fixes coccicheck warning: fs/btrfs/print-tree.c:320:3-4: Unneeded semicolon Reported-by: Hulk Robot <hulkci@huawei.com> Signed-off-by: zhengbin <zhengbin13@huawei.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-11-18btrfs: rename extent buffer block group item accessorsDavid Sterba1-3/+3
Accessors defined by BTRFS_SETGET_FUNCS take a raw extent buffer and manipulate the items there, there's no special prefix required. The block group accessors had _disk_ because previously the names were occupied by the on-stack accessors. As this has been addressed in the previous patch, we can now unify the naming. Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Reviewed-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-07-02btrfs: switch extent_buffer write_locks from atomic to intDavid Sterba1-1/+1
The write_locks is either 0 or 1 and always updated under the lock, so we don't need the atomic_t semantics. Reviewed-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-07-02btrfs: switch extent_buffer spinning_writers from atomic to intDavid Sterba1-1/+1
The spinning_writers is either 0 or 1 and always updated under the lock, so we don't need the atomic_t semantics. Signed-off-by: David Sterba <dsterba@suse.com>
2019-07-02btrfs: switch extent_buffer blocking_writers from atomic to intDavid Sterba1-1/+1
The blocking_writers is either 0 or 1 and always updated under the lock, so we don't need the atomic_t semantics. Reviewed-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2019-04-29btrfs: get fs_info from eb in btrfs_leaf_free_spaceDavid Sterba1-1/+1
We can read fs_info from extent buffer and can drop it from the parameters. Signed-off-by: David Sterba <dsterba@suse.com>
2018-08-06btrfs: annotate unlikely branches after V0 extent type removalDavid Sterba1-1/+1
The v0 extent type checks are the right case for the unlikely annotations as we don't expect to ever see them, so let's give the compiler some hint. Reviewed-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2018-08-06btrfs: Add graceful handling of V0 extentsNikolay Borisov1-3/+6
Following the removal of the v0 handling code let's be courteous and print an error message when such extents are handled. In the cases where we have a transaction just abort it, otherwise just call btrfs_handle_fs_error. Both cases result in the FS being re-mounted RO. In case the error handling would be too intrusive, leave the BUG_ON in place, like extent_data_ref_count, other proper handling would catch that earlier. Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2018-08-06btrfs: Remove V0 extent supportNikolay Borisov1-29/+1
The v0 compat code was introduced in commit 5d4f98a28c7d ("Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)") 9 years ago, which was merged in 2.6.31. This means that the code is there to support filesystems which are _VERY_ old and if you are using btrfs on such an old kernel, you have much bigger problems. This coupled with the fact that no one is likely testing/maintining this code likely means it has bugs lurking. All things considered I think 43 kernel releases later it's high time this remnant of the past got removed. This patch removes all code wrapped in #ifdefs but leaves the BUG_ONs in case we have a v0 with no support intact as a sort of safety-net. Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2018-08-06btrfs: Get rid of the confusing btrfs_file_extent_inline_lenQu Wenruo1-2/+2
We used to call btrfs_file_extent_inline_len() to get the uncompressed data size of an inlined extent. However this function is hiding evil, for compressed extent, it has no choice but to directly read out ram_bytes from btrfs_file_extent_item. While for uncompressed extent, it uses item size to calculate the real data size, and ignoring ram_bytes completely. In fact, for corrupted ram_bytes, due to above behavior kernel btrfs_print_leaf() can't even print correct ram_bytes to expose the bug. Since we have the tree-checker to verify all EXTENT_DATA, such mismatch can be detected pretty easily, thus we can trust ram_bytes without the evil btrfs_file_extent_inline_len(). Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2018-05-28btrfs: print-tree: Add eb locking status output for debug buildQu Wenruo1-0/+21
It's pretty handy if we can get the debug output for locking status of an extent buffer, specially for race condition related debugging. So add the following output for btrfs_print_tree() and btrfs_print_leaf(): - refs - write_locks (as w:%d) - read_locks (as r:%d) - blocking_writers (as bw:%d) - blocking_readers (as br:%d) - spinning_writers (as sw:%d) - spinning_readers (as sr:%d) - lock_owner - current->pid Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> [ update comment ] Signed-off-by: David Sterba <dsterba@suse.com>
2018-04-20btrfs: print-tree: debugging output enhancementQu Wenruo1-10/+15
This patch enhances the following things: - tree block header * add generation and owner output for node and leaf - node pointer generation output - allow btrfs_print_tree() to not follow nodes * just like btrfs-progs Please note that, although function btrfs_print_tree() is not called by anyone right now, it's still a pretty useful function to debug kernel. So that function is still kept for later use. Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: Lu Fengqi <lufq.fnst@cn.fujitsu.com> Signed-off-by: David Sterba <dsterba@suse.com>
2018-04-12btrfs: replace GPL boilerplate by SPDX -- sourcesDavid Sterba1-14/+1
Remove GPL boilerplate text (long, short, one-line) and keep the rest, ie. personal, company or original source copyright statements. Add the SPDX header. Signed-off-by: David Sterba <dsterba@suse.com>
2018-03-31btrfs: Validate child tree block's level and first keyQu Wenruo1-3/+7
We have several reports about node pointer points to incorrect child tree blocks, which could have even wrong owner and level but still with valid generation and checksum. Although btrfs check could handle it and print error message like: leaf parent key incorrect 60670574592 Kernel doesn't have enough check on this type of corruption correctly. At least add such check to read_tree_block() and btrfs_read_buffer(), where we need two new parameters @level and @first_key to verify the child tree block. The new @level check is mandatory and all call sites are already modified to extract expected level from its call chain. While @first_key is optional, the following call sites are skipping such check: 1) Root node/leaf As ROOT_ITEM doesn't contain the first key, skip @first_key check. 2) Direct backref Only parent bytenr and level is known and we need to resolve the key all by ourselves, skip @first_key check. Another note of this verification is, it needs extra info from nodeptr or ROOT_ITEM, so it can't fit into current tree-checker framework, which is limited to node/leaf boundary. Signed-off-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2017-08-21Btrfs: add one more sanity check for shared ref typeLiu Bo1-6/+21
Every shared ref has a parent tree block, which can be get from btrfs_extent_inline_ref_offset(). And the tree block must be aligned to the nodesize, so we'd know this inline ref is not valid if this block's bytenr is not aligned to the nodesize, in which case, most likely the ref type has been misused. This adds the above mentioned check and also updates print_extent_item() called by btrfs_print_leaf() to point out the invalid ref while printing the tree structure. Signed-off-by: Liu Bo <bo.li.liu@oracle.com> Signed-off-by: David Sterba <dsterba@suse.com>
2017-08-21Btrfs: remove BUG() in print_extent_itemLiu Bo1-1/+4
btrfs_print_leaf() is used in btrfs_get_extent_inline_ref_type, so here we really want to print the invalid value of ref type instead of causing a kernel panic. Signed-off-by: Liu Bo <bo.li.liu@oracle.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2017-08-16btrfs: get fs_info from eb in btrfs_print_tree, remove argumentDavid Sterba1-2/+4
Signed-off-by: David Sterba <dsterba@suse.com>
2017-08-16btrfs: get fs_info from eb in btrfs_print_leaf, remove argumentDavid Sterba1-2/+4
Signed-off-by: David Sterba <dsterba@suse.com>
2017-06-19Btrfs: let btrfs_print_leaf print more about block groupLiu Bo1-2/+5
This adds chunk_objectid and flags, with flags we can recognize whether the block group is about data or metadata. Signed-off-by: Liu Bo <bo.li.liu@oracle.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2016-12-06btrfs: take an fs_info directly when the root is not used otherwiseJeff Mahoney1-8/+7
There are loads of functions in btrfs that accept a root parameter but only use it to obtain an fs_info pointer. Let's convert those to just accept an fs_info pointer directly. Signed-off-by: Jeff Mahoney <jeffm@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2016-12-06btrfs: root->fs_info cleanup, add fs_info convenience variablesJeff Mahoney1-3/+5
In routines where someptr->fs_info is referenced multiple times, we introduce a convenience variable. This makes the code considerably more readable. Signed-off-by: Jeff Mahoney <jeffm@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2016-12-06btrfs: pull node/sector/stripe sizes out of root and into fs_infoJeff Mahoney1-1/+1
We track the node sizes per-root, but they never vary from the values in the superblock. This patch messes with the 80-column style a bit, but subsequent patches to factor out root->fs_info into a convenience variable fix it up again. Signed-off-by: Jeff Mahoney <jeffm@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2016-09-26btrfs: convert printk(KERN_* to use pr_* callsJeff Mahoney1-31/+31
This patch converts printk(KERN_* style messages to use the pr_* versions. One side effect is that anything that was KERN_DEBUG is now automatically a dynamic debug message. Signed-off-by: Jeff Mahoney <jeffm@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2016-09-26btrfs: unsplit printed stringsJeff Mahoney1-32/+18
CodingStyle chapter 2: "[...] never break user-visible strings such as printk messages, because that breaks the ability to grep for them." This patch unsplits user-visible strings. Signed-off-by: Jeff Mahoney <jeffm@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2016-09-26Btrfs: add error handling for extent buffer in print treeLiu Bo1-0/+7
Somehow we missed btrfs_print_tree when last time we updated error handling for read_extent_block(). This keeps us from getting a NULL pointer panic when btrfs_print_tree's read_extent_block() fails. Signed-off-by: Liu Bo <bo.li.liu@oracle.com> Signed-off-by: David Sterba <dsterba@suse.com>
2016-02-11btrfs: teach print_leaf about temporary item subtypesDavid Sterba1-0/+11
Signed-off-by: David Sterba <dsterba@suse.com>
2016-02-11btrfs: teach print_leaf about permanent item subtypesDavid Sterba1-2/+10
Signed-off-by: David Sterba <dsterba@suse.com>
2014-10-02btrfs: remove parameter blocksize from read_tree_blockDavid Sterba1-1/+0
We know the tree block size, no need to pass it around. Signed-off-by: David Sterba <dsterba@suse.cz>
2014-09-17btrfs: use nodesize everywhere, kill leafsizeDavid Sterba1-1/+1
The nodesize and leafsize were never of different values. Unify the usage and make nodesize the one. Cleanup the redundant checks and helpers. Shaves a few bytes from .text: text data bss dec hex filename 852418 24560 23112 900090 dbbfa btrfs.ko.before 851074 24584 23112 898770 db6d2 btrfs.ko.after Signed-off-by: David Sterba <dsterba@suse.cz> Signed-off-by: Chris Mason <clm@fb.com>
2014-09-17btrfs: kill the key type accessor helpersDavid Sterba1-1/+1
btrfs_set_key_type and btrfs_key_type are used inconsistently along with open coded variants. Other members of btrfs_key are accessed directly without any helpers anyway. Signed-off-by: David Sterba <dsterba@suse.cz> Signed-off-by: Chris Mason <clm@fb.com>
2014-07-03Btrfs: fix btrfs_print_leaf for skinny metadataJosef Bacik1-4/+5
We wouldn't actuall print the extent information if we had a skinny metadata item, this fixes that. Thanks, Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Chris Mason <clm@fb.com>
2014-01-29Btrfs: don't use ram_bytes for uncompressed inline itemsChris Mason1-1/+1
If we truncate an uncompressed inline item, ram_bytes isn't updated to reflect the new size. The fixe uses the size directly from the item header when reading uncompressed inlines, and also fixes truncate to update the size as it goes. Reported-by: Jens Axboe <axboe@fb.com> Signed-off-by: Chris Mason <clm@fb.com> CC: stable@vger.kernel.org
2014-01-28Btrfs: convert printk to btrfs_ and fix BTRFS prefixFrank Holton1-1/+1
Convert all applicable cases of printk and pr_* to the btrfs_* macros. Fix all uses of the BTRFS prefix. Signed-off-by: Frank Holton <fholton@gmail.com> Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Chris Mason <clm@fb.com>
2013-11-11btrfs: drop unused parameter from btrfs_item_nrRoss Kirk1-1/+1
Remove unused eb parameter from btrfs_item_nr Signed-off-by: Ross Kirk <ross.kirk@gmail.com> Reviewed-by: David Sterba <dsterba@suse.cz> Signed-off-by: Josef Bacik <jbacik@fusionio.com> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2013-09-01Btrfs: Remove superfluous casts from u64 to unsigned long longGeert Uytterhoeven1-51/+28
u64 is "unsigned long long" on all architectures now, so there's no need to cast it when formatting it using the "ll" length modifier. Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Josef Bacik <jbacik@fusionio.com> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2013-09-01Btrfs: support printing UUID tree elementsStefan Behrens1-0/+24
This commit adds support to print UUID tree elements to print-tree.c. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Josef Bacik <jbacik@fusionio.com> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2013-09-01Btrfs: Print key type in decimal everywhereStefan Behrens1-2/+2
This is confusing, sometimes the key type is printed in hex (without a leading "0x" which makes things even more complicated), sometimes in decimal... Change it to be in decimal everywhere. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Josef Bacik <jbacik@fusionio.com> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2013-05-06Btrfs: Include the device in most error printk()sSimon Kirby1-5/+4
With more than one btrfs volume mounted, it can be very difficult to find out which volume is hitting an error. btrfs_error() will print this, but it is currently rigged as more of a fatal error handler, while many of the printk()s are currently for debugging and yet-unhandled cases. This patch just changes the functions where the device information is already available. Some cases remain where the root or fs_info is not passed to the function emitting the error. This may introduce some confusion with volumes backed by multiple devices emitting errors referring to the primary device in the set instead of the one on which the error occurred. Use btrfs_printk(fs_info, format, ...) rather than writing the device string every time, and introduce macro wrappers ala XFS for brevity. Since the function already cannot be used for continuations, print a newline as part of the btrfs_printk() message rather than at each caller. Signed-off-by: Simon Kirby <sim@hostway.ca> Reviewed-by: David Sterba <dsterba@suse.cz> Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2013-02-20btrfs: add missing break in btrfs_print_leaf()Eric Sandeen1-0/+1
I don't think that BTRFS_DEV_EXTENT_KEY is supposed to fall through to BTRFS_DEV_STATS_KEY ... Signed-off-by: Eric Sandeen <sandeen@redhat.com> Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2012-12-12Btrfs: introduce a btrfs_dev_replace_item typeStefan Behrens1-0/+3
Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de> Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-05-30Btrfs: read device stats on mount, write modified ones during commitStefan Behrens1-0/+3
The device statistics are written into the device tree with each transaction commit. Only modified statistics are written. When a filesystem is mounted, the device statistics for each involved device are read from the device tree and used to initialize the counters. Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de>
2011-10-20btrfs: fix oops on failure pathDaniel J Blueman1-2/+6
If lookup_extent_backref fails, path->nodes[0] reasonably could be null along with other callers of btrfs_print_leaf, so ensure we have a valid extent buffer before dereferencing. Signed-off-by: Daniel J Blueman <daniel.blueman@gmail.com>
2011-01-28btrfs: fix missing break in switch phraseliubo1-0/+1
There is a missing break in switch, fix it. Signed-off-by: Liu Bo <liubo2009@cn.fujitsu.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-22Btrfs: remove of redundant btrfs_header_levelDaniel Cadete1-3/+3
This removes the continues call's of btrfs_header_level. One call of btrfs_header_level(c) its enough. Signed-off-by Daniel Cadete <danielncadete10@gmail.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)Yan Zheng1-17/+138
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: Yan Zheng <zheng.yan@oracle.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-01-05Btrfs: Fix checkpatch.pl warningsChris Mason1-29/+44
There were many, most are fixed now. struct-funcs.c generates some warnings but these are bogus. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-10-29Btrfs: Add zlib compression supportChris Mason1-3/+4
This is a large change for adding compression on reading and writing, both for inline and regular extents. It does some fairly large surgery to the writeback paths. Compression is off by default and enabled by mount -o compress. Even when the -o compress mount option is not used, it is possible to read compressed extents off the disk. If compression for a given set of pages fails to make them smaller, the file is flagged to avoid future compression attempts later. * While finding delalloc extents, the pages are locked before being sent down to the delalloc handler. This allows the delalloc handler to do complex things such as cleaning the pages, marking them writeback and starting IO on their behalf. * Inline extents are inserted at delalloc time now. This allows us to compress the data before inserting the inline extent, and it allows us to insert an inline extent that spans multiple pages. * All of the in-memory extent representations (extent_map.c, ordered-data.c etc) are changed to record both an in-memory size and an on disk size, as well as a flag for compression. From a disk format point of view, the extent pointers in the file are changed to record the on disk size of a given extent and some encoding flags. Space in the disk format is allocated for compression encoding, as well as encryption and a generic 'other' field. Neither the encryption or the 'other' field are currently used. In order to limit the amount of data read for a single random read in the file, the size of a compressed extent is limited to 128k. This is a software only limit, the disk format supports u64 sized compressed extents. In order to limit the ram consumed while processing extents, the uncompressed size of a compressed extent is limited to 256k. This is a software only limit and will be subject to tuning later. Checksumming is still done on compressed extents, and it is done on the uncompressed version of the data. This way additional encodings can be layered on without having to figure out which encoding to checksum. Compression happens at delalloc time, which is basically singled threaded because it is usually done by a single pdflush thread. This makes it tricky to spread the compression load across all the cpus on the box. We'll have to look at parallel pdflush walks of dirty inodes at a later time. Decompression is hooked into readpages and it does spread across CPUs nicely. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-10-09Btrfs: Remove offset field from struct btrfs_extent_refYan Zheng1-2/+1
The offset field in struct btrfs_extent_ref records the position inside file that file extent is referenced by. In the new back reference system, tree leaves holding references to file extent are recorded explicitly. We can scan these tree leaves very quickly, so the offset field is not required. This patch also makes the back reference system check the objectid when extents are in deleting. Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
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