ext4: move check under lock scope to close a race.

[firefly-linux-kernel-4.4.55.git] / fs / xfs / xfs_file.c

diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index 1cdba95c78cb3e2475de29e0b6d88df3604e4cdf..a2e1cb8a568bf9d45e32c43539a2e6f8b56d83f4 100644 (file)
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -36,6 +36,7 @@
 #include "xfs_trace.h"
 #include "xfs_log.h"
 #include "xfs_icache.h"
+#include "xfs_pnfs.h"
 
 #include <linux/aio.h>
 #include <linux/dcache.h>
@@ -396,7 +397,8 @@ STATIC int                          /* error (positive) */
 xfs_zero_last_block(
        struct xfs_inode        *ip,
        xfs_fsize_t             offset,
-       xfs_fsize_t             isize)
+       xfs_fsize_t             isize,
+       bool                    *did_zeroing)
 {
        struct xfs_mount        *mp = ip->i_mount;
        xfs_fileoff_t           last_fsb = XFS_B_TO_FSBT(mp, isize);
@@ -424,6 +426,7 @@ xfs_zero_last_block(
        zero_len = mp->m_sb.sb_blocksize - zero_offset;
        if (isize + zero_len > offset)
                zero_len = offset - isize;
+       *did_zeroing = true;
        return xfs_iozero(ip, isize, zero_len);
 }
 
@@ -442,7 +445,8 @@ int                                 /* error (positive) */
 xfs_zero_eof(
        struct xfs_inode        *ip,
        xfs_off_t               offset,         /* starting I/O offset */
-       xfs_fsize_t             isize)          /* current inode size */
+       xfs_fsize_t             isize,          /* current inode size */
+       bool                    *did_zeroing)
 {
        struct xfs_mount        *mp = ip->i_mount;
        xfs_fileoff_t           start_zero_fsb;
@@ -464,7 +468,7 @@ xfs_zero_eof(
         * We only zero a part of that block so it is handled specially.
         */
        if (XFS_B_FSB_OFFSET(mp, isize) != 0) {
-               error = xfs_zero_last_block(ip, offset, isize);
+               error = xfs_zero_last_block(ip, offset, isize, did_zeroing);
                if (error)
                        return error;
        }
@@ -524,6 +528,7 @@ xfs_zero_eof(
                if (error)
                        return error;
 
+               *did_zeroing = true;
                start_zero_fsb = imap.br_startoff + imap.br_blockcount;
                ASSERT(start_zero_fsb <= (end_zero_fsb + 1));
        }
@@ -554,6 +559,10 @@ restart:
        if (error)
                return error;
 
+       error = xfs_break_layouts(inode, iolock);
+       if (error)
+               return error;
+
        /*
         * If the offset is beyond the size of the file, we need to zero any
         * blocks that fall between the existing EOF and the start of this
@@ -562,13 +571,15 @@ restart:
         * having to redo all checks before.
         */
        if (*pos > i_size_read(inode)) {
+               bool    zero = false;
+
                if (*iolock == XFS_IOLOCK_SHARED) {
                        xfs_rw_iunlock(ip, *iolock);
                        *iolock = XFS_IOLOCK_EXCL;
                        xfs_rw_ilock(ip, *iolock);
                        goto restart;
                }
-               error = xfs_zero_eof(ip, *pos, i_size_read(inode));
+               error = xfs_zero_eof(ip, *pos, i_size_read(inode), &zero);
                if (error)
                        return error;
        }
@@ -822,6 +833,7 @@ xfs_file_fallocate(
        struct xfs_inode        *ip = XFS_I(inode);
        long                    error;
        enum xfs_prealloc_flags flags = 0;
+       uint                    iolock = XFS_IOLOCK_EXCL;
        loff_t                  new_size = 0;
 
        if (!S_ISREG(inode->i_mode))
@@ -830,7 +842,11 @@ xfs_file_fallocate(
                     FALLOC_FL_COLLAPSE_RANGE | FALLOC_FL_ZERO_RANGE))
                return -EOPNOTSUPP;
 
-       xfs_ilock(ip, XFS_IOLOCK_EXCL);
+       xfs_ilock(ip, iolock);
+       error = xfs_break_layouts(inode, &iolock);
+       if (error)
+               goto out_unlock;
+
        if (mode & FALLOC_FL_PUNCH_HOLE) {
                error = xfs_free_file_space(ip, offset, len);
                if (error)
@@ -894,7 +910,7 @@ xfs_file_fallocate(
        }
 
 out_unlock:
-       xfs_iunlock(ip, XFS_IOLOCK_EXCL);
+       xfs_iunlock(ip, iolock);
        return error;
 }