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2008-06-24[GFS2] fix gfs2 block allocation (cleaned up)Benjamin Marzinski
This patch fixes bz 450641. This patch changes the computation for zero_metapath_length(), which it renames to metapath_branch_start(). When you are extending the metadata tree, The indirect blocks that point to the new data block must either diverge from the existing tree either at the inode, or at the first indirect block. They can diverge at the first indirect block because the inode has room for 483 pointers while the indirect blocks have room for 509 pointers, so when the tree is grown, there is some free space in the first indirect block. What metapath_branch_start() now computes is the height where the first indirect block for the new data block is located. It can either be 1 (if the indirect block diverges from the inode) or 2 (if it diverges from the first indirect block). Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2008-03-31[GFS2] Streamline quota lock/check for no-quota caseSteven Whitehouse
This patch streamlines the quota checking in the "no quota" case by making the check inline in the calling function, thus reducing the number of function calls. Eventually we might be able to remove the checks from the gfs2_quota_lock() and gfs2_quota_check() functions, but currently we can't as there are a very few places in the code which need to call these functions directly still. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com> Cc: Abhijith Das <adas@redhat.com>
2008-03-31[GFS2] possible null pointer dereference fixupCyrill Gorcunov
gfs2_alloc_get may fail so we have to check it to prevent NULL pointer dereference. Signed-off-by: Cyrill Gorcunov <gorcunov@gamil.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2008-03-31[GFS2] Allow bmap to allocate extentsSteven Whitehouse
We've supported mapping of extents when no block allocation is required for some time. This patch extends that to mapping of extents when an allocation has been requested. In that case we try to allocate as many blocks as are requested, but we might return fewer in case there is something preventing us from returning the complete amount (e.g. an already allocated block is in the way). Currently the only code path which can actually request multiple data blocks in a single bmap call is the page_mkwrite path and even then it only happens if there are multiple blocks per page. What this patch does do however, is merge the allocation requests for metadata (growing the metadata tree in either height or depth) with the allocation of the data blocks in the case that both are needed. This results in lower overheads even in the single block allocation case. The one thing which we can't handle here at the moment is unstuffing. I would like to be able to do that, but the problem which arises is that in order to unstuff one has to get a locked page from the page cache which results in locking problems in the (usual) case that the caller is holding the page lock on the page it wishes to map. So that case will have to be addressed in future patches. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2008-03-31[GFS2] Get inode buffer only once per block map callSteven Whitehouse
In the case that we needed to grow the height of the metadata tree we were looking up the inode buffer and then brelse()ing it despite the fact that it is needed later in the block map process. This patch ensures that we look up the inode's buffer once and only once during the block map process. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2008-03-31[GFS2] Eliminate (almost) duplicate field from gfs2_inodeSteven Whitehouse
The blocks counter is almost a duplicate of the i_blocks field in the VFS inode. The only difference is that i_blocks can be only 32bits long for 32bit arch without large single file support. Since GFS2 doesn't handle the non-large single file case (for 32 bit anyway) this adds a new config dependency on 64BIT || LSF. This has always been the case, however we've never explicitly said so before. Even if we do add support for the non-LSF case, we will still not require this field to be duplicated since we will not be able to access oversized files anyway. So the net result of all this is that we shave 8 bytes from a gfs2_inode and get our config deps correct. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2008-03-31[GFS2] Add a function to interate over an extentSteven Whitehouse
This adds a function (currently the only use is during mapping of already allocated blocks, but watch this space) which iterates over a number of pointers in a block and returns the extent length. If the initial pointer is 0 (i.e. unallocated) it will return the number of unallocated blocks in the extent. If the initial pointer is allocated, then it returns the number of contiguously allocated blocks in the extent. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2008-03-31[GFS2] The case of the missing asteriskSteven Whitehouse
A dereference was forgotten. This adds it back correctly. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2008-03-31[GFS2] Add extent allocation to block allocatorSteven Whitehouse
Rather than having to allocate a single block at a time, this patch allows the block allocator to allocate an extent. Since there is no difference (so far as the block allocator is concerned) between data blocks and indirect blocks, it is posible to allocate a single extent and for the caller to unrevoke just the blocks required for indirect blocks. Currently the only bit of GFS2 to make use of this feature is the build height function. The intention is that gfs2_block_map will be changed to make use of this feature in future patches. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2008-03-31[GFS2] Merge gfs2_alloc_meta and gfs2_alloc_dataSteven Whitehouse
Thanks to the preceeding patches, the only difference between these two functions is their name. We can thus merge them and call the new function gfs2_alloc_block to reflect the fact that it can allocate either kind of block. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2008-03-31[GFS2] Update gfs2_trans_add_unrevoke to accept extentsSteven Whitehouse
By adding an extra argument to gfs2_trans_add_unrevoke we can now specify an extent length of blocks to unrevoke. This means that we only need to make one pass through the list for each extent rather than each block. Currently the only extent length which is used is 1, but that will change in the future. Also gfs2_trans_add_unrevoke is removed from gfs2_alloc_meta since its the only difference between this and gfs2_alloc_data which is left. This will allow a future patch to merge these two functions into one (i.e. one call to allocate both data and metadata in a single extent in the future). Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2008-03-31[GFS2] Reduce inode size by merging fieldsSteven Whitehouse
There were three fields being used to keep track of the location of the most recently allocated block for each inode. These have been merged into a single field in order to better keep the data and metadata for an inode close on disk, and also to reduce the space required for storage. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2008-03-31[GFS2] Introduce array of buffers to struct metapathSteven Whitehouse
The reason for doing this is to allow all the block mapping code to share the same array. As a result we can remove two arguments from lookup_metapath since they are now returned via the array. We also add a function to drop all refs to buffer heads when we are done with the metapath. The build_height function shares the struct metapath, but currently still frees its own buffers, and this will change in a future patch. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2008-03-31[GFS2] Move part of gfs2_block_map into a separate functionSteven Whitehouse
This is required to enable future changes to the block mapping code. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2008-03-31[GFS2] Misc fixupsBob Peterson
This patch contains two small fixups that didn't fit elsewhere. They are: (1) get rid of temp variable in find_metapath. (2) Remove vestigial "ret" variable from gfs2_writepage_common. Signed-off-by: Bob Peterson <rpeterso@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2008-03-31[GFS2] Get rid of unneeded parameter in gfs2_rlist_allocBob Peterson
This patch removed the unnecessary parameter from function gfs2_rlist_alloc. The parameter was always passed in as 0. Signed-off-by: Bob Peterson <rpeterso@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2008-03-31[GFS2] Streamline indirect pointer tree height calculationSteven Whitehouse
This patch improves the calculation of the tree height in order to reduce the number of operations which are carried out on each call to gfs2_block_map. In the common case, we now make a single comparison, rather than calculating the required tree height from scratch each time. Also in the case that the tree does need some extra height, we start from the current height rather from zero when we work out what the new height ought to be. In addition the di_height field is moved into the inode proper and reduced in size to a u8 since the value must be between 0 and GFS2_MAX_META_HEIGHT (10). Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2008-03-31[GFS2] Speed up gfs2_write_alloc_required, deprecate gfs2_extent_mapSteven Whitehouse
This patch removes the call to gfs2_extent_map from gfs2_write_alloc_required, instead we call gfs2_block_map directly. This results in fewer overall calls to gfs2_block_map in the multi-block case. Also, gfs2_extent_map is marked as deprecated so that people know that its going away as soon as all the callers have been converted. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2008-02-05Pagecache zeroing: zero_user_segment, zero_user_segments and zero_userChristoph Lameter
Simplify page cache zeroing of segments of pages through 3 functions zero_user_segments(page, start1, end1, start2, end2) Zeros two segments of the page. It takes the position where to start and end the zeroing which avoids length calculations and makes code clearer. zero_user_segment(page, start, end) Same for a single segment. zero_user(page, start, length) Length variant for the case where we know the length. We remove the zero_user_page macro. Issues: 1. Its a macro. Inline functions are preferable. 2. The KM_USER0 macro is only defined for HIGHMEM. Having to treat this special case everywhere makes the code needlessly complex. The parameter for zeroing is always KM_USER0 except in one single case that we open code. Avoiding KM_USER0 makes a lot of code not having to be dealing with the special casing for HIGHMEM anymore. Dealing with kmap is only necessary for HIGHMEM configurations. In those configurations we use KM_USER0 like we do for a series of other functions defined in highmem.h. Since KM_USER0 is depends on HIGHMEM the existing zero_user_page function could not be a macro. zero_user_* functions introduced here can be be inline because that constant is not used when these functions are called. Also extract the flushing of the caches to be outside of the kmap. [akpm@linux-foundation.org: fix nfs and ntfs build] [akpm@linux-foundation.org: fix ntfs build some more] Signed-off-by: Christoph Lameter <clameter@sgi.com> Cc: Steven French <sfrench@us.ibm.com> Cc: Michael Halcrow <mhalcrow@us.ibm.com> Cc: <linux-ext4@vger.kernel.org> Cc: Steven Whitehouse <swhiteho@redhat.com> Cc: Trond Myklebust <trond.myklebust@fys.uio.no> Cc: "J. Bruce Fields" <bfields@fieldses.org> Cc: Anton Altaparmakov <aia21@cantab.net> Cc: Mark Fasheh <mark.fasheh@oracle.com> Cc: David Chinner <dgc@sgi.com> Cc: Michael Halcrow <mhalcrow@us.ibm.com> Cc: Steven French <sfrench@us.ibm.com> Cc: Steven Whitehouse <swhiteho@redhat.com> Cc: Trond Myklebust <trond.myklebust@fys.uio.no> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-01-25[GFS2] Fix write alloc required shortcut calculationSteven Whitehouse
The comparison was being made against the wrong quantity. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2008-01-25[GFS2] gfs2_alloc_required performanceBob Peterson
This is a small I/O performance enhancement to gfs2. (Actually, it is a rework of an earlier version I got wrong). The idea here is to check if the write extends past the last block in the file. If so, the function can save itself a lot of time and trouble because it knows an allocate will be required. Benchmarks like iozone should see better performance. Signed-off-by: Bob Peterson <rpeterso@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2008-01-25[GFS2] Reduce inode size by moving i_alloc out of lineSteven Whitehouse
It is possible to reduce the size of GFS2 inodes by taking the i_alloc structure out of the gfs2_inode. This patch allocates the i_alloc structure whenever its needed, and frees it afterward. This decreases the amount of low memory we use at the expense of requiring a memory allocation for each page or partial page that we write. A quick test with postmark shows that the overhead is not measurable and I also note that OCFS2 use the same approach. In the future I'd like to solve the problem by shrinking down the size of the members of the i_alloc structure, but for now, this reduces the immediate problem of using too much low-memory on x86 and doesn't add too much overhead. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2008-01-25[GFS2] Only fetch the dinode once in block_mapBob Peterson
Function gfs2_block_map was often looking up the disk inode twice. This optimizes it so that only does it once. Signed-off-by: Bob Peterson <rpeterso@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2008-01-25[GFS2] Remove function gfs2_get_blockBob Peterson
This patch is just a cleanup. Function gfs2_get_block() just calls function gfs2_block_map reversing the last two parameters. By reversing the parameters, gfs2_block_map() may be called directly and function gfs2_get_block may be eliminated altogether. Since this function is done for every block operation, this streamlines the code and makes it a little bit more efficient. Signed-off-by: Bob Peterson <rpeterso@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2008-01-25[GFS2] Add gfs2_is_writeback()Steven Whitehouse
This adds a function "gfs2_is_writeback()" along the lines of the existing "gfs2_is_jdata()" in order to clean up the code and make the various tests for the inode mode more obvious. It also fixes the PageChecked() logic where we were resetting the flag too early in the case of an error path. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-10-10[GFS2] Fix ordering of dirty/journal for ordered buffer unstuffingBob Peterson
Signed-off-by: Bob Peterson <rpeterso@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-10-10[GFS2] Don't mark jdata dirty in gfs2_unstuffer_page()Steven Whitehouse
Journaled data is marked dirty by gfs2_unpin and should not be marked dirty here. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-10-10[GFS2] Reduce truncate IO trafficWendy Cheng
Current GFS2 setattr call unconditionally invokes do_shrink even the requested size and actual file size are equal. This has generated large amount of extra IOs found during NFS benchmark runs. This patch moves the relevant logic out of shrink code path. Since setattr is a system call, the time stamps update is still required. Signed-off-by: S. Wendy Cheng <wcheng@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-07-09[GFS2] Fix gfs2_block_truncate_page err returnS. Wendy Cheng
Code segment inside gfs2_block_truncate_page() doesn't set the return code correctly. This causes NFSD erroneously returns EIO back to client with setattr procedure call (truncate error). Signed-off-by: S. Wendy Cheng <wcheng@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-07-09[GFS2] Add nanosecond timestamp featureSteven Whitehouse
This adds a nanosecond timestamp feature to the GFS2 filesystem. Due to the way that the on-disk format works, older filesystems will just appear to have this field set to zero. When mounted by an older version of GFS2, the filesystem will simply ignore the extra fields so that it will again appear to have whole second resolution, so that its trivially backward compatible. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-07-09[GFS2] Fix sign problem in quota/statfs and cleanup _host structuresSteven Whitehouse
This patch fixes some sign issues which were accidentally introduced into the quota & statfs code during the endianess annotation process. Also included is a general clean up which moves all of the _host structures out of gfs2_ondisk.h (where they should not have been to start with) and into the places where they are actually used (often only one place). Also those _host structures which are not required any more are removed entirely (which is the eventual plan for all of them). The conversion routines from ondisk.c are also moved into the places where they are actually used, which for almost every one, was just one single place, so all those are now static functions. This also cleans up the end of gfs2_ondisk.h which no longer needs the #ifdef __KERNEL__. The net result is a reduction of about 100 lines of code, many functions now marked static plus the bug fixes as mentioned above. For good measure I ran the code through sparse after making these changes to check that there are no warnings generated. This fixes Red Hat bz #239686 Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-07-09[GFS2] Clean up inode number handlingSteven Whitehouse
This patch cleans up the inode number handling code. The main difference is that instead of looking up the inodes using a struct gfs2_inum_host we now use just the no_addr member of this structure. The tests relating to no_formal_ino can then be done by the calling code. This has advantages in that we want to do different things in different code paths if the no_formal_ino doesn't match. In the NFS patch we want to return -ESTALE, but in the ->lookup() path, its a bug in the fs if the no_formal_ino doesn't match and thus we can withdraw in this case. In order to later fix bz #201012, we need to be able to look up an inode without knowing no_formal_ino, as the only information that is known to us is the on-disk location of the inode in question. This patch will also help us to fix bz #236099 at a later date by cleaning up a lot of the code in that area. There are no user visible changes as a result of this patch and there are no changes to the on-disk format either. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-07-09[GFS2] use zero_user_pageNate Diller
Use zero_user_page() instead of open-coding it. Signed-off-by: Nate Diller <nate.diller@gmail.com> Cc: Steven Whitehouse <swhiteho@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2007-02-14[PATCH] remove many unneeded #includes of sched.hTim Schmielau
After Al Viro (finally) succeeded in removing the sched.h #include in module.h recently, it makes sense again to remove other superfluous sched.h includes. There are quite a lot of files which include it but don't actually need anything defined in there. Presumably these includes were once needed for macros that used to live in sched.h, but moved to other header files in the course of cleaning it up. To ease the pain, this time I did not fiddle with any header files and only removed #includes from .c-files, which tend to cause less trouble. Compile tested against 2.6.20-rc2 and 2.6.20-rc2-mm2 (with offsets) on alpha, arm, i386, ia64, mips, powerpc, and x86_64 with allnoconfig, defconfig, allmodconfig, and allyesconfig as well as a few randconfigs on x86_64 and all configs in arch/arm/configs on arm. I also checked that no new warnings were introduced by the patch (actually, some warnings are removed that were emitted by unnecessarily included header files). Signed-off-by: Tim Schmielau <tim@physik3.uni-rostock.de> Acked-by: Russell King <rmk+kernel@arm.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-05[GFS2] use CURRENT_TIME_SEC instead of get_seconds in gfs2Eric Sandeen
I was looking something else up and came across this... I don't honestly have a good reason to change it other than to make it like every other Linux filesystem in this regard. ;-) It doesn't functionally change anything, but makes some lines shorter. :) I'm also curious; why does gfs2 have 64-bits of on-disk timestamps, but not in timespec_t format, and only stores second resolutions? Seems like you're halfway to sub-second resolutions already. I suppose if that gets implemented then all of the below should instead be CURRENT_TIME not CURRENT_TIME_SEC. Signed-off-by: Eric Sandeen <sandeen@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2006-11-30[GFS2] Tidy up bmap & fix boundary bugSteven Whitehouse
This moves the locking for bmap into the bmap function itself rather than using a wrapper function. It also fixes a bug where the boundary flag was set on the wrong bh. Also the flags on the mapped bh are reset earlier in the function to ensure that they are 100% correct on the error path. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2006-11-30[GFS2] Remove gfs2_inode_attr_inSteven Whitehouse
This function wasn't really doing the right thing. There was no need to update the inode size at this point and the updating of the i_blocks field has now been moved to the places where di_blocks is updated. A result of this patch and some those preceeding it is that unlocking a glock is now a much more efficient process, since there is no longer any requirement to copy data from the gfs2 inode into the vfs inode at this point. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2006-11-30[GFS2] Shrink gfs2_inode (6) - di_atime/di_mtime/di_ctimeSteven Whitehouse
Remove the di_[amc]time fields and use inode->i_[amc]time fields instead. This saves 24 bytes from the gfs2_inode. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2006-11-30[GFS2] Shrink gfs2_inode (4) - di_uid/di_gidSteven Whitehouse
Remove duplicate di_uid/di_gid fields in favour of using inode->i_uid/inode->i_gid instead. This saves 8 bytes. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2006-11-30[GFS2] Shrink gfs2_inode (3) - di_modeSteven Whitehouse
This removes the duplicate di_mode field in favour of using the inode->i_mode field. This saves 4 bytes. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2006-11-30[GFS2] Change argument of gfs2_dinode_outSteven Whitehouse
Everywhere this was called, a struct gfs2_inode was available, but despite that, it was always called with a struct gfs2_dinode as an argument. By making this change it paves the way to start eliminating fields duplicated between the kernel's struct inode and the struct gfs2_dinode. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2006-11-30[GFS2] gfs2 misc endianness annotationsAl Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2006-10-20[GFS2] Fix bmap to map extents properlySteven Whitehouse
This fix means that bmap will map extents of the length requested by the VFS rather than guessing at it, or just mapping one block at a time. The other callers of gfs2_block_map are audited to ensure they send the correct max extent lengths (i.e. set bh->b_size correctly). Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2006-10-02[GFS2] Remove uneeded endian conversionSteven Whitehouse
In many places GFS2 was calling the endian conversion routines for an inode even when only a single field, or a few fields might have changed. As a result we were copying lots of data needlessly. This patch replaces those calls with conversion of just the required fields in each case. This should be faster and easier to understand. There are still other places which suffer from this problem, but this is a start in the right direction. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2006-09-25[GFS2/DLM] Fix trailing whitespaceSteven Whitehouse
As per Andrew Morton's request, removed trailing whitespace. Cc: Andrew Morton <akpm@osdl.org> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2006-09-21[GFS2] Tidy up meta_io codeSteven Whitehouse
Fix a bug in the directory reading code, where we might have dereferenced a NULL pointer in case of OOM. Updated the directory code to use the new & improved version of gfs2_meta_ra() which now returns the first block that was being read. Previously it was releasing it requiring following code to grab the block again at each point it was called. Also turned off readahead on directory lookups since we are reading a hash table, and therefore reading the entries in order is very unlikely. Readahead is still used for all other calls to the directory reading function (e.g. when growing the hash table). Removed the DIO_START constant. Everywhere this was used, it was used to unconditionally start i/o aside from a couple of places, so I've removed it and made the couple of exceptions to this rule into separate functions. Also hunted through the other DIO flags and removed them as arguments from functions which were always called with the same combination of arguments. Updated gfs2_meta_indirect_buffer to be a bit more efficient and hopefully also be a bit easier to read. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2006-09-19[GFS2] Export lm_interface to kernel headersFabio Massimo Di Nitto
lm_interface.h has a few out of the tree clients such as GFS1 and userland tools. Right now, these clients keeps a copy of the file in their build tree that can go out of sync. Move lm_interface.h to include/linux, export it to userland and clean up fs/gfs2 to use the new location. Signed-off-by: Fabio M. Di Nitto <fabbione@ubuntu.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2006-09-19[GFS2] inode-diet-eliminate-i_blksize-and-use-a-per-superblock-default-vs-gfs2akpm@osdl.org
i_blksize got removed in -mm. Cc: Steven Whitehouse <swhiteho@redhat.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2006-09-18[GFS2] Map multiple blocks at once where possibleSteven Whitehouse
This is a tidy up of the GFS2 bmap code. The main change is that the bh is passed to gfs2_block_map allowing the flags to be set directly rather than having to repeat that code several times in ops_address.c. At the same time, the extent mapping code from gfs2_extent_map has been moved into gfs2_block_map. This allows all calls to gfs2_block_map to map extents in the case that no allocation is taking place. As a result reads and non-allocating writes should be faster. A quick test with postmark appears to support this. There is a limit on the number of blocks mapped in a single bmap call in that it will only ever map blocks which are pointed to from a single pointer block. So in other words, it will never try to do additional i/o in order to satisfy read-ahead. The maximum number of blocks is thus somewhat less than 512 (the GFS2 4k block size minus the header divided by sizeof(u64)). I've further limited the mapping of "normal" blocks to 32 blocks (to avoid extra work) since readpages() will currently read a maximum of 32 blocks ahead (128k). Some further work will probably be needed to set a suitable value for DIO as well, but for now thats left at the maximum 512 (see ops_address.c:gfs2_get_block_direct). There is probably a lot more that can be done to improve bmap for GFS2, but this is a good first step. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2006-09-07[GFS2] More style changesJan Engelhardt
Remove redundant brackets Signed-off-by: Jan Engelhardt <jengelh@linux01.gwdg.de> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>