Message ID | 1339638836-19990-1-git-send-email-ashish.sangwan2@gmail.com |
---|---|
State | Superseded, archived |
Headers | show |
Hi. Eric. This is the patch for punch hole issue. Thanks. 2012/6/14, Ashish Sangwan <ashishsangwan2@gmail.com>: > The current implementation of hole punch uses the same code path as for > truncate in which the block removal starts from the end of the file and > continue backwards removing extents and in the process decreases the > count of valid entries in the extent header of extent index. > If all the extents under current extent index are removed than this index > is also removed and the number of valid entries in the "depth -1" > extent header is decreased by 1. > > Whether to continue removing extents or not is decided by the return value > of function ext4_ext_more_to_rm() which checks 2 conditions: > a) if there are no more indexes to process. > b) if the number of entries are decreased in the header of "depth -1". > > In case of hole punch, if the last block to be removed is not part of the > last extent index than this index will not be deleted, hence the number of > valid entries in the extent header of "depth - 1" will remain as it is and > ext4_ext_more_to_rm will return 0 although the required blocks are not > yet removed. > > This patch fixes the above mentioned problem as instead of removing the > extents from the end of file, it starts removing the blocks from the > particular extent from which removing blocks is actually required and > continue backward until done. > > Signed-off-by: Ashish Sangwan <ashish.sangwan2@gmail.com> > Signed-off-by: Namjae Jeon <linkinjeon@gmail.com> > --- > fs/ext4/extents.c | 43 +++++++++++++++++++++++++++---------------- > 1 files changed, 27 insertions(+), 16 deletions(-) > > diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c > index 91341ec..27c3a30 100644 > --- a/fs/ext4/extents.c > +++ b/fs/ext4/extents.c > @@ -2570,10 +2570,10 @@ static int ext4_ext_remove_space(struct inode > *inode, ext4_lblk_t start, > { > struct super_block *sb = inode->i_sb; > int depth = ext_depth(inode); > - struct ext4_ext_path *path; > + struct ext4_ext_path *path = NULL; > ext4_fsblk_t partial_cluster = 0; > handle_t *handle; > - int i, err; > + int i = 0, err; > > ext_debug("truncate since %u to %u\n", start, end); > > @@ -2606,8 +2606,12 @@ again: > } > depth = ext_depth(inode); > ex = path[depth].p_ext; > - if (!ex) > + if (!ex) { > + ext4_ext_drop_refs(path); > + kfree(path); > + path = NULL; > goto cont; > + } > > ee_block = le32_to_cpu(ex->ee_block); > > @@ -2637,8 +2641,6 @@ again: > if (err < 0) > goto out; > } > - ext4_ext_drop_refs(path); > - kfree(path); > } > cont: > > @@ -2647,19 +2649,27 @@ cont: > * after i_size and walking into the tree depth-wise. > */ > depth = ext_depth(inode); > - path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 1), GFP_NOFS); > - if (path == NULL) { > - ext4_journal_stop(handle); > - return -ENOMEM; > - } > - path[0].p_depth = depth; > - path[0].p_hdr = ext_inode_hdr(inode); > + if (path) { > + int k = i = depth; > + while (--k >= 0) > + path[k].p_block = > + le16_to_cpu(path[k].p_hdr->eh_entries)+1; > + } else { > + path = > + kzalloc(sizeof(struct ext4_ext_path) * (depth + 1), GFP_NOFS); > + if (path == NULL) { > + ext4_journal_stop(handle); > + return -ENOMEM; > + } > + path[0].p_depth = depth; > + path[0].p_hdr = ext_inode_hdr(inode); > > - if (ext4_ext_check(inode, path[0].p_hdr, depth)) { > - err = -EIO; > - goto out; > + if (ext4_ext_check(inode, path[0].p_hdr, depth)) { > + err = -EIO; > + goto out; > + } > } > - i = err = 0; > + err = 0; > > while (i >= 0 && err == 0) { > if (i == depth) { > @@ -2773,6 +2783,7 @@ cont: > out: > ext4_ext_drop_refs(path); > kfree(path); > + path = NULL; > if (err == -EAGAIN) > goto again; > ext4_journal_stop(handle); > -- > 1.7.2.3 > > -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Hi Ted, Lukas, Eric, Did any of you get a chance to look at it? On Fri, Jun 22, 2012 at 6:19 AM, Namjae Jeon <linkinjeon@gmail.com> wrote: > Hi. Eric. > > This is the patch for punch hole issue. > > Thanks. > -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Mon, 2 Jul 2012, Ashish Sangwan wrote: > Date: Mon, 2 Jul 2012 11:03:26 +0530 > From: Ashish Sangwan <ashishsangwan2@gmail.com> > To: sandeen@redhat.com, Lukáš Czerner <lczerner@redhat.com>, > Ted Tso <tytso@mit.edu> > Cc: linux-kernel@vger.kernel.org, linux-ext4@vger.kernel.org, > Namjae Jeon <linkinjeon@gmail.com> > Subject: Re: [PATCH v2] ext4: fix hole punch failure when depth is greater > than 0 > > Hi Ted, Lukas, Eric, > > Did any of you get a chance to look at it? I am sorry for the delay. I have been trying to reproduce this problem without any success so far. But is was on ppc64 machine, so I'll try that on x86_64 and then review the patch. Thanks! -Lukas > > On Fri, Jun 22, 2012 at 6:19 AM, Namjae Jeon <linkinjeon@gmail.com> wrote: > > Hi. Eric. > > > > This is the patch for punch hole issue. > > > > Thanks. > > >
I will try to elaborate more about the problem and steps to reproduce: Linux version 3.4.0 on X86 box. Step1: First create a small partition as it would be easy to fragment quickly. The main intent for fragmenting the partition is to create a file with at least 2 extent indexes. You can also choose some other method to create such a file. I created 200Mb partition and while formating used blocksize as 4KB and used attached script to fragment. This script fragments the partition such that each extent is exactly 6FS blocks OR 24KB in length. Linux#> ./fragment.sh /mnt/ 6+0 records in 6+0 records out 24576 bytes (24.0KB) copied, 0.087997 seconds, 272.7KB/s cp: write error: No space left on device Partition filled rm: can't remove '/mnt//file1.7564': No such file or directory fragmented partition /mnt/ with 24KB files Step2: Create a file with 342 extents i.e 2 extent indexes [root@sputnik ashish]# dd if=linux-3.4.tar.bz2 of=check_1 bs=24576 count=342 342+0 records in 342+0 records out 8404992 bytes (8.4 MB) copied, 0.0913289 s, 92.0 MB/s [root@sputnik ashish]# cp check_1 /mnt/check_2 [root@sputnik ashish]# debugfs /dev/sdb1 debugfs 1.41.14 (22-Dec-2010) debugfs: dump_extents check_2 Level Entries Logical Physical Length Flags 0/ 1 1/ 2 0 - 2039 32792 2040 1/ 1 1/340 0 - 5 5771 - 5776 6 1/ 1 2/340 6 - 11 5783 - 5788 6 <------- continue like wise till 340 -------------> 1/ 1 340/340 2034 - 2039 9835 - 9840 6 0/ 1 2/ 2 2040 - 2051 5764 12 1/ 1 1/ 2 2040 - 2045 9847 - 9852 6 1/ 1 2/ 2 2046 - 2051 9859 - 9864 6 Step3: Punch hole at offset 4KB and length of hole is also 4KB There is attached fallocate.c [root@sputnik ashish]# ./fallacote.x86 /mnt/check_2 ret = 0 [root@sputnik ashish]# Check extent tree: [root@sputnik ashish]# debugfs /dev/sdb1 debugfs 1.41.14 (22-Dec-2010) debugfs: dump_extents check_2 Level Entries Logical Physical Length Flags 0/ 1 1/ 3 0 - 5 32792 6 1/ 1 1/ 2 0 - 1 5771 - 5772 2 1/ 1 2/ 2 2 - 5 5773 - 5776 4 0/ 1 2/ 3 6 - 2039 9871 2034 1/ 1 1/339 6 - 11 5783 - 5788 6 <------- continue like wise till 339 -------------> 1/ 1 339/339 2034 - 2039 9835 - 9840 6 0/ 1 3/ 3 2040 - 2051 5764 12 1/ 1 1/ 2 2040 - 2045 9847 - 9852 6 1/ 1 2/ 2 2046 - 2051 9859 - 9864 6 It is clearly visible that punching hole just split the first extent into 2 but failed to remove the required blocks. Step4: To cross check, take diff of 2 files. [root@sputnik ashish]# diff check_1 /mnt/check_2 [root@sputnik ashish]# The 2 files are exactly same. After applying this patch, correct results will be observed. On Mon, Jul 2, 2012 at 2:42 PM, Lukáš Czerner <lczerner@redhat.com> wrote: > On Mon, 2 Jul 2012, Ashish Sangwan wrote: > >> Date: Mon, 2 Jul 2012 11:03:26 +0530 >> From: Ashish Sangwan <ashishsangwan2@gmail.com> >> To: sandeen@redhat.com, Lukáš Czerner <lczerner@redhat.com>, >> Ted Tso <tytso@mit.edu> >> Cc: linux-kernel@vger.kernel.org, linux-ext4@vger.kernel.org, >> Namjae Jeon <linkinjeon@gmail.com> >> Subject: Re: [PATCH v2] ext4: fix hole punch failure when depth is greater >> than 0 >> >> Hi Ted, Lukas, Eric, >> >> Did any of you get a chance to look at it? > > I am sorry for the delay. I have been trying to reproduce this > problem without any success so far. But is was on ppc64 machine, so > I'll try that on x86_64 and then review the patch. > > Thanks! > -Lukas > >> >> On Fri, Jun 22, 2012 at 6:19 AM, Namjae Jeon <linkinjeon@gmail.com> wrote: >> > Hi. Eric. >> > >> > This is the patch for punch hole issue. >> > >> > Thanks. >> > >>
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c index 91341ec..27c3a30 100644 --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -2570,10 +2570,10 @@ static int ext4_ext_remove_space(struct inode *inode, ext4_lblk_t start, { struct super_block *sb = inode->i_sb; int depth = ext_depth(inode); - struct ext4_ext_path *path; + struct ext4_ext_path *path = NULL; ext4_fsblk_t partial_cluster = 0; handle_t *handle; - int i, err; + int i = 0, err; ext_debug("truncate since %u to %u\n", start, end); @@ -2606,8 +2606,12 @@ again: } depth = ext_depth(inode); ex = path[depth].p_ext; - if (!ex) + if (!ex) { + ext4_ext_drop_refs(path); + kfree(path); + path = NULL; goto cont; + } ee_block = le32_to_cpu(ex->ee_block); @@ -2637,8 +2641,6 @@ again: if (err < 0) goto out; } - ext4_ext_drop_refs(path); - kfree(path); } cont: @@ -2647,19 +2649,27 @@ cont: * after i_size and walking into the tree depth-wise. */ depth = ext_depth(inode); - path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 1), GFP_NOFS); - if (path == NULL) { - ext4_journal_stop(handle); - return -ENOMEM; - } - path[0].p_depth = depth; - path[0].p_hdr = ext_inode_hdr(inode); + if (path) { + int k = i = depth; + while (--k >= 0) + path[k].p_block = + le16_to_cpu(path[k].p_hdr->eh_entries)+1; + } else { + path = + kzalloc(sizeof(struct ext4_ext_path) * (depth + 1), GFP_NOFS); + if (path == NULL) { + ext4_journal_stop(handle); + return -ENOMEM; + } + path[0].p_depth = depth; + path[0].p_hdr = ext_inode_hdr(inode); - if (ext4_ext_check(inode, path[0].p_hdr, depth)) { - err = -EIO; - goto out; + if (ext4_ext_check(inode, path[0].p_hdr, depth)) { + err = -EIO; + goto out; + } } - i = err = 0; + err = 0; while (i >= 0 && err == 0) { if (i == depth) { @@ -2773,6 +2783,7 @@ cont: out: ext4_ext_drop_refs(path); kfree(path); + path = NULL; if (err == -EAGAIN) goto again; ext4_journal_stop(handle);