| Message ID | 1314750513-10045-5-git-send-email-achender@linux.vnet.ibm.com |
|---|---|
| State | Rejected, archived |
| Headers | show |
On 2011-08-30, at 6:28 PM, Allison Henderson wrote: > This patch modifies the fallocate routine to lock i_mutex during > the punch hole operation. > > Yongqiang noticed that the vfs layer locks i_mutex for truncate, > but not fallocate, so the fallocate routine will need to take > care of locking i_mutex. Otherwise a page may be mapped after > punch hole has released the pages, but before i_data_sem is > locked to release the blocks in the extent tree. If the VFS is locking i_mutex for truncate, shouldn't the locking for fallocate() also be done in the VFS? > Signed-off-by: Allison Henderson <achender@linux.vnet.ibm.com> > --- > :100644 100644 9124cd2... 007fb08... M fs/ext4/extents.c > fs/ext4/extents.c | 10 +++++++--- > 1 files changed, 7 insertions(+), 3 deletions(-) > > diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c > index 9124cd2..007fb08 100644 > --- a/fs/ext4/extents.c > +++ b/fs/ext4/extents.c > @@ -3774,8 +3774,13 @@ long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len) > if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE)) > return -EOPNOTSUPP; > > - if (mode & FALLOC_FL_PUNCH_HOLE) > - return ext4_punch_hole(file, offset, len); > + mutex_lock(&inode->i_mutex); > + > + if (mode & FALLOC_FL_PUNCH_HOLE) { > + ret = ext4_punch_hole(file, offset, len); > + mutex_unlock(&inode->i_mutex); > + return ret; > + } > > trace_ext4_fallocate_enter(inode, offset, len, mode); > map.m_lblk = offset >> blkbits; > @@ -3789,7 +3794,6 @@ long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len) > * credits to insert 1 extent into extent tree > */ > credits = ext4_chunk_trans_blocks(inode, max_blocks); > - mutex_lock(&inode->i_mutex); > ret = inode_newsize_ok(inode, (len + offset)); > if (ret) { > mutex_unlock(&inode->i_mutex); > -- > 1.7.1 > > -- > 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 Cheers, Andreas -- 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 08/30/2011 05:31 PM, Andreas Dilger wrote: > On 2011-08-30, at 6:28 PM, Allison Henderson wrote: >> This patch modifies the fallocate routine to lock i_mutex during >> the punch hole operation. >> >> Yongqiang noticed that the vfs layer locks i_mutex for truncate, >> but not fallocate, so the fallocate routine will need to take >> care of locking i_mutex. Otherwise a page may be mapped after >> punch hole has released the pages, but before i_data_sem is >> locked to release the blocks in the extent tree. > > If the VFS is locking i_mutex for truncate, shouldn't the locking for > fallocate() also be done in the VFS? Alrighty, I will do some poking around with this idea first. I dont know if other files systems are already locking i_mutex during fallocate, and it may be the case that not all filesystems need i_mutex locked for fallocate. So I'll do a little research first, but I will post back with what I find. Thx! Allison Henderson > >> Signed-off-by: Allison Henderson<achender@linux.vnet.ibm.com> >> --- >> :100644 100644 9124cd2... 007fb08... M fs/ext4/extents.c >> fs/ext4/extents.c | 10 +++++++--- >> 1 files changed, 7 insertions(+), 3 deletions(-) >> >> diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c >> index 9124cd2..007fb08 100644 >> --- a/fs/ext4/extents.c >> +++ b/fs/ext4/extents.c >> @@ -3774,8 +3774,13 @@ long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len) >> if (mode& ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE)) >> return -EOPNOTSUPP; >> >> - if (mode& FALLOC_FL_PUNCH_HOLE) >> - return ext4_punch_hole(file, offset, len); >> + mutex_lock(&inode->i_mutex); >> + >> + if (mode& FALLOC_FL_PUNCH_HOLE) { >> + ret = ext4_punch_hole(file, offset, len); >> + mutex_unlock(&inode->i_mutex); >> + return ret; >> + } >> >> trace_ext4_fallocate_enter(inode, offset, len, mode); >> map.m_lblk = offset>> blkbits; >> @@ -3789,7 +3794,6 @@ long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len) >> * credits to insert 1 extent into extent tree >> */ >> credits = ext4_chunk_trans_blocks(inode, max_blocks); >> - mutex_lock(&inode->i_mutex); >> ret = inode_newsize_ok(inode, (len + offset)); >> if (ret) { >> mutex_unlock(&inode->i_mutex); >> -- >> 1.7.1 >> >> -- >> 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 > > > Cheers, Andreas > > > > > -- 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 2011-08-31, at 12:49 PM, Allison Henderson wrote: > On 08/30/2011 05:31 PM, Andreas Dilger wrote: >> On 2011-08-30, at 6:28 PM, Allison Henderson wrote: >>> This patch modifies the fallocate routine to lock i_mutex during >>> the punch hole operation. >>> >>> Yongqiang noticed that the vfs layer locks i_mutex for truncate, >>> but not fallocate, so the fallocate routine will need to take >>> care of locking i_mutex. Otherwise a page may be mapped after >>> punch hole has released the pages, but before i_data_sem is >>> locked to release the blocks in the extent tree. >> >> If the VFS is locking i_mutex for truncate, shouldn't the locking for >> fallocate() also be done in the VFS? > > Alrighty, I will do some poking around with this idea first. I dont know if other files systems are already locking i_mutex during fallocate, and it may be the case that not all filesystems need i_mutex locked for fallocate. So I'll do a little research first, but I will post back with what I find. Thx! Probably a good idea to bring up this issue on linux-fsdevel. >>> Signed-off-by: Allison Henderson<achender@linux.vnet.ibm.com> >>> --- >>> :100644 100644 9124cd2... 007fb08... M fs/ext4/extents.c >>> fs/ext4/extents.c | 10 +++++++--- >>> 1 files changed, 7 insertions(+), 3 deletions(-) >>> >>> diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c >>> index 9124cd2..007fb08 100644 >>> --- a/fs/ext4/extents.c >>> +++ b/fs/ext4/extents.c >>> @@ -3774,8 +3774,13 @@ long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len) >>> if (mode& ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE)) >>> return -EOPNOTSUPP; >>> >>> - if (mode& FALLOC_FL_PUNCH_HOLE) >>> - return ext4_punch_hole(file, offset, len); >>> + mutex_lock(&inode->i_mutex); >>> + >>> + if (mode& FALLOC_FL_PUNCH_HOLE) { >>> + ret = ext4_punch_hole(file, offset, len); >>> + mutex_unlock(&inode->i_mutex); >>> + return ret; >>> + } >>> >>> trace_ext4_fallocate_enter(inode, offset, len, mode); >>> map.m_lblk = offset>> blkbits; >>> @@ -3789,7 +3794,6 @@ long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len) >>> * credits to insert 1 extent into extent tree >>> */ >>> credits = ext4_chunk_trans_blocks(inode, max_blocks); >>> - mutex_lock(&inode->i_mutex); >>> ret = inode_newsize_ok(inode, (len + offset)); >>> if (ret) { >>> mutex_unlock(&inode->i_mutex); >>> -- >>> 1.7.1 >>> >>> -- >>> 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 >> >> >> Cheers, Andreas >> >> >> >> >> > Cheers, Andreas -- 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
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c index 9124cd2..007fb08 100644 --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -3774,8 +3774,13 @@ long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len) if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE)) return -EOPNOTSUPP; - if (mode & FALLOC_FL_PUNCH_HOLE) - return ext4_punch_hole(file, offset, len); + mutex_lock(&inode->i_mutex); + + if (mode & FALLOC_FL_PUNCH_HOLE) { + ret = ext4_punch_hole(file, offset, len); + mutex_unlock(&inode->i_mutex); + return ret; + } trace_ext4_fallocate_enter(inode, offset, len, mode); map.m_lblk = offset >> blkbits; @@ -3789,7 +3794,6 @@ long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len) * credits to insert 1 extent into extent tree */ credits = ext4_chunk_trans_blocks(inode, max_blocks); - mutex_lock(&inode->i_mutex); ret = inode_newsize_ok(inode, (len + offset)); if (ret) { mutex_unlock(&inode->i_mutex);
This patch modifies the fallocate routine to lock i_mutex during the punch hole operation. Yongqiang noticed that the vfs layer locks i_mutex for truncate, but not fallocate, so the fallocate routine will need to take care of locking i_mutex. Otherwise a page may be mapped after punch hole has released the pages, but before i_data_sem is locked to release the blocks in the extent tree. Signed-off-by: Allison Henderson <achender@linux.vnet.ibm.com> --- :100644 100644 9124cd2... 007fb08... M fs/ext4/extents.c fs/ext4/extents.c | 10 +++++++--- 1 files changed, 7 insertions(+), 3 deletions(-)